Maize variety X6N745

ABSTRACT

A novel maize variety designated X6N745 and seed, plants and plant parts thereof, produced by crossing Pioneer Hi-Bred International, Inc. proprietary inbred maize varieties. Methods for producing a maize plant that comprises crossing maize variety X6N745 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X6N745 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize variety X6N745, the seed, the plant produced from the seed, and variants, mutants, and minor modifications of maize variety X6N745. This invention further relates to methods for producing maize varieties derived from maize variety X6N745 and to the maize varieties derived by the use of those methods.

FIELD OF THE INVENTION

This invention relates generally to the field of maize breeding,specifically relating to maize variety designated X6N745.

BACKGROUND OF THE INVENTION

The goal of hybrid development is to combine, in a single hybrid,various desirable traits. For field crops, these traits may includeresistance to diseases and insects, resistance to heat and drought,reducing the time to crop maturity, greater yield, and better agronomicquality. With mechanical harvesting of many crops, uniformity of plantcharacteristics such as germination, stand establishment, growth rate,maturity, and plant and ear height is important. Traditional plantbreeding is an important tool in developing new and improved commercialcrops.

SUMMARY OF THE INVENTION

According to the invention, there is provided a maize variety, seed,plant, and its parts designated as X6N745, produced by crossing twoPioneer Hi-Bred International, Inc. proprietary maize inbred varieties.This invention relates to the maize variety X6N745, the seed, the plantand its parts produced from the seed, and variants, mutants and minormodifications of maize X6N745. This invention also relates to processesfor making a maize plant containing in its genetic material one or moretraits introgressed into X6N745 through backcross conversion and/ortransformation, and to the maize seed, plant and plant part produced bysuch introgression. This invention further relates to methods forproducing maize varieties derived from maize variety X6N745 and to themaize varieties produced by the use of those processes.

DEFINITIONS

Certain definitions used in the specification are provided below. Alsoin the examples that follow, a number of terms are used herein. In orderto provide a clear and consistent understanding of the specification andclaims, including the scope to be given such terms, the followingdefinitions are provided. NOTE: ABS is in absolute terms and % MN ispercent of the mean for the experiments in which the inbred or hybridwas grown. PCT designates that the trait is calculated as a percentage.% NOT designates the percentage of plants that did not exhibit a trait.For example, STKLDG % NOT is the percentage of plants in a plot thatwere not stalk lodged. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ABIOTIC STRESS TOLERANCE. Resistance to non-biological sources of stressconferred by traits such as nitrogen utilization efficiency, alterednitrogen responsiveness, drought resistance cold, and salt resistance.

ABTSTK=ARTIFICIAL BRITTLE STALK. A count of the number of “snapped”plants per plot following machine snapping. A snapped plant has itsstalk completely snapped at a node between the base of the plant and thenode above the ear. Expressed as percent of plants that did not snap.

ADF=PERCENT ACID DETERGENT FIBER. The percent of dry matter that is aciddetergent fiber in chopped whole plant forage.

ALEURONE: A thin layer of cells just beneath the pericarp of the seed.

ALLELE. Any of one or more alternative forms of a genetic sequence. In adiploid cell or organism, the two alleles of a given sequence typicallyoccupy corresponding loci on a pair of homologous chromosomes.

ALTER. The utilization of up-regulation, down-regulation, or genesilencing.

ANTHESIS. The time of a flower's opening.

ANTHOCYANIN OF BRACE ROOTS: The degree of red coloration of the braceroots after exposure to sunlight taken at flowering. Brace rootanthocyanin is scored 1-5 where 1=no red color, 2=pink, 3=red, 4=darkred, and 5=purple.

ANTIOXIDANT. A chemical compound or substance that inhibits oxidation,including but not limited to tocopherol or tocotrienols.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance. Data are collected only whensufficient selection pressure exists in the experiment measured.

BACKCROSSING. Process in which a breeder crosses a progeny variety backto one of the parental genotypes one or more times.

BACKCROSS PROGENY. Progeny plants produced by crossing a maize inbredparent of X6N745 plant with maize plants that comprise desired traits orloci, selecting F1 progeny plants that comprise the desired traits orloci, and crossing the selected F1 progeny plants with the X6N745 plants1 or more times to produce backcross progeny plants that comprise saidtraits or loci.

BAR GLUMES: (glume band) The presence or absence of horizontal lines atthe base of the glumes on tassel florets.

BARPLT=BARREN PLANTS. The percent of plants per plot that were notbarren, i.e., lack an ear with grain, or have an ear with only a fewscattered kernels.

BORBMN=ARTIFICIAL BRITTLE STALK MEAN. The mean percent of plants not“snapped” in a plot following artificial selection pressure. A snappedplant has its stalk completely snapped at a node between the base of theplant and the node above the ear. Expressed as percent of plants thatdid not snap. A high number is good and indicates tolerance to brittlesnapping.

BRANCH ANGLE FROM CENTRAL SPIKE: The adaxial angle measured in degreeswith a protractor on the top primary lateral tassel branch at flowering.

BRENGMN=BRITTLE STALK ENERGY MEAN. The mean amount of energy per unitarea needed to artificially brittle snap a corn stalk. A high number isgood and indicates tolerance to brittle snapping.

BREEDING. The genetic manipulation of living organisms.

BREEDING CROSS. A cross to introduce new genetic material into a plantfor the development of a new variety. For example, one could cross plantA with plant B, wherein plant B would be genetically different fromplant A. After the breeding cross, the resulting F1 plants could then beselfed or sibbed for one, two, three or more times (F1, F2, F3, etc.)until a new inbred variety is developed. For clarification, such newinbred variety would be within a pedigree distance of one breeding crossof plants A and B.

BRLPNE=ARTIFICIAL ROOT LODGING EARLY SEASON. The percent of plants notroot lodged in a plot following artificial selection pressure appliedprior to flowering. A plant is considered root lodged if it leans fromthe vertical axis at an approximately 30 degree angle or greater.Expressed as percent of plants that did not root lodge. A high number isgood and indicates tolerance to preflowering root lodging.

BRLPNL=ARTIFICIAL ROOT LODGING LATE SEASON. The percent of plants notroot lodged in a plot following artificial selection pressure duringgrain fill. A plant is considered root lodged if it leans from thevertical axis at an approximately 30 degree angle or greater. Expressedas percent of plants that did not root lodge. A high number is good andindicates tolerance to late season root lodging.

BRTSTK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

CARBOHYDRATE. Organic compounds comprising carbon, oxygen and hydrogen,including sugars, starches and cellulose.

CELL. Cell as used herein includes a plant cell, whether isolated, intissue culture or incorporated in a plant or plant part.

CLDTST=COLD TEST. The percent of plants that germinate under cold testconditions.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance. Data are collected only when sufficientselection pressure exists in the experiment measured.

COMRST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance. Data are collected only when sufficient selection pressureexists in the experiment measured.

COMMON SMUT (Ustilago maydis): A 1 to 9 visual rating indicating theresistance to Common Smut. A higher score indicates a higher resistance.Data is collected only when sufficient selection pressure exists in theexperiment measured.

CP=PERCENT OF CRUDE PROTEIN. The percent of dry matter that is crudeprotein in chopped whole plant forage.

CROSS POLLINATION. A plant is cross pollinated if the pollen comes froma flower on a different plant from a different family or variety. Crosspollination excludes sib and self pollination.

CROSSING. The combination of genetic material by traditional methodssuch as a breeding cross or backcross, but also including protoplastfusion and other molecular biology methods of combining genetic materialfrom two sources.

CRWNIS=CORN ROOTWORM NODE INJURY SCALE (Diabrotica sp.). A 0-3 visualrating based on the proportion of roots pruned by corn rootworm larvaeto less than 1.5 inches of the crown. 0 indicates no feeding, 3indicates a total of 3 entire nodes of roots pruned.

D/D=DRYDOWN. This represents the relative rate at which a variety willreach acceptable harvest moisture compared to other varieties on a 1 to9 rating scale. A high score indicates a variety that dries relativelyfast while a low score indicates a variety that dries slowly.

DIPERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance. Dataare collected only when sufficient selection pressure exists in theexperiment measured.

DIPLOID PLANT PART. Refers to a plant part or cell that has the samediploid genotype as X6N745.

DIPROT=DIPLODIA STALK ROT SCORE. Score of stalk rot severity due toDiplodia (Diplodia maydis). Expressed as a 1 to 9 score with 9 beinghighly resistant. Data are collected only when sufficient selectionpressure exists in the experiment measured.

DM=PERCENT OF DRY MATTER. The percent of dry material in chopped wholeplant silage.

DRPEAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest. Data are collected only when sufficient selection pressureexists in the experiment measured.

D/T=DROUGHT TOLERANCE. This represents a 1 to 9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

EARHT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured incentimeters.

EARMLD=GENERAL EAR MOLD. Visual rating (1 to 9 score) where a 1 is verysusceptible and a 9 is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

EAR NODE: The node on the main stem that bears the top or primary ear.

EAR POSITION: The orientation of the primary ear 65 days after 50% silk.Ear position is scored as 1=upright, 2=horizontal, and 3=pendant(downward or drooping).

EAR SHANK LENGTH: The measurement of the structure from the butt of theprimary ear to the ear node on the main stem.

EARSZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

EBTSTK=EARLY BRITTLE STALK. A count of the number of “snapped” plantsper plot following severe winds when the corn plant is experiencing veryrapid vegetative growth in the V5-V8 stage. Expressed as percent ofplants that did not snap. Data are collected only when sufficientselection pressure exists in the experiment measured.

ECB1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance. Data are collected only whensufficient selection pressure exists in the experiment measured.

ECB21T=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk. Data are collected only when sufficient selection pressure existsin the experiment measured.

ECB2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1to 9 visual rating indicating post flowering degree of stalk breakageand other evidence of feeding by second generation European Corn Borer.A higher score indicates a higher resistance. Data are collected onlywhen sufficient selection pressure exists in the experiment measured.

ECBDPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation European Corn Borer infestation. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

ECBLSI=EUROPEAN CORN BORER LATE SEASON INTACT (Ostrinia nubilalis). A 1to 9 visual rating indicating late season intactness of the corn plantgiven damage (stalk breakage above and below the top ear) causedprimarily by 2^(nd) and/or 3^(rd) generation ECB larval feeding beforeharvest. A higher score is good and indicates more intact plants. Dataare collected only when sufficient selection pressure exists in theexperiment measured.

EGRWTH=EARLY GROWTH. This is a measure of the relative height and sizeof a corn seedling at the 2-4 leaf stage of growth. This is a visualrating (1 to 9), with 1 being weak or slow growth, 5 being averagegrowth and 9 being strong growth. Taller plants, wider leaves, moregreen mass and darker color constitute a higher score. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

ELITE INBRED. An inbred that contributed desirable qualities when usedto produce commercial hybrids. An elite inbred may also be used infurther breeding for the purpose of developing further improvedvarieties.

ENDOSPERM: The nutritive tissue (starch) within the seed that surroundsthe embryo.

ERTLDG=EARLY ROOT LODGING. The percentage of plants that do not rootlodge prior to or around anthesis; plants that lean from the verticalaxis at an approximately 30 degree angle or greater would be counted asroot lodged. Data are collected only when sufficient selection pressureexists in the experiment measured.

ERTLPN=EARLY ROOT LODGING. An estimate of the percentage of plants thatdo not root lodge prior to or around anthesis; plants that lean from thevertical axis at an approximately 30 degree angle or greater would beconsidered as root lodged. Data are collected only when sufficientselection pressure exists in the experiment measured.

ERTLSC=EARLY ROOT LODGING SCORE. Score for severity of plants that leanfrom a vertical axis at an approximate 30 degree angle or greater whichtypically results from strong winds prior to or around floweringrecorded within 2 weeks of a wind event. Expressed as a 1 to 9 scorewith 9 being no lodging. Data are collected only when sufficientselection pressure exists in the experiment measured.

ESSENTIAL AMINO ACIDS. Amino acids that cannot be synthesized de novo byan organism and therefore must be supplied in the diet.

ESTCNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on a perplot basis for the inbred or hybrid.

EYESPT=EYE SPOT (Kabatiella zeae or Aureobasidium zeae). A 1 to 9 visualrating indicating the resistance to Eye Spot. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

EXPRESSING. Having the genetic potential such that under the rightconditions, the phenotypic trait is present.

FATTY ACID. A carboxylic acid (or organic acid), often with a longaliphatic tail (long chains), either saturated or unsaturated.

F1 PROGENY. Progeny plants produced by crossing plants of maize varietyX6N745 with plants of another maize line.

FUSERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium Ear Rot. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, whichassumes that maize growth occurs in the temperature range 50 degreesF.-86 degrees F. and that temperatures outside this range slow downgrowth; the maximum daily heat unit accumulation is 36 and the minimumdaily heat unit accumulation is 0. The seasonal accumulation of GDU is amajor factor in determining maturity zones.

GDUSHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred variety or hybrid variety to haveapproximately 50 percent of the plants shedding pollen and is measuredfrom the time of planting. Growing degree units are calculated by theBarger Method, where the heat units for a 24-hour period are:

${G\; D\; U} = {\frac{\left( {{Max}.\mspace{11mu}{temp}.\mspace{11mu}{+ \mspace{11mu}{{Min}.\mspace{11mu}{temp}.}}} \right)}{2} - 50}$

The highest maximum temperature used is 86 degrees F. and the lowestminimum temperature used is 50 degrees F. For each inbred or hybrid ittakes a certain number of GDUs to reach various stages of plantdevelopment.

GDUSLK=GDU TO SILK. The number of growing degree units required for aninbred variety or hybrid variety to have approximately 50 percent of theplants with silk emergence from time of planting. Growing degree unitsare calculated by the Barger Method as given in GDU SHD definition.

GENE SILENCING. The interruption or suppression of the expression of agene at the level of transcription or translation.

GENOTYPE. Refers to the genetic constitution of a cell or organism.

GIBERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9 visualrating indicating the resistance to Gibberella Ear Rot. A higher scoreindicates a higher resistance. Data are collected only when sufficientselection pressure exists in the experiment measured.

GIBROT=GIBBERELLA STALK ROT SCORE. Score of stalk rot severity due toGibberella (Gibberella zeae). Expressed as a 1 to 9 score with 9 beinghighly resistant. Data are collected only when sufficient selectionpressure exists in the experiment measured.

GLFSPT=GRAY LEAF SPOT (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

GOSWLT=GOSS' WILT (Corynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

GRNAPP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on a 1 to 9 relative rating system with a higher numberindicating the variety responds well to high plant densities for yieldrelative to other varieties. A 1, 5, and 9 would represent very poor,average, and very good yield response, respectively, to increased plantdensity.

HAPLOID PLANT PART. Refers to a plant part or cell that has the samehaploid genotype as X6N745.

HCBLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporium carbonum).A 1 to 9 visual rating indicating the resistance to Helminthosporiuminfection. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates thepercentage of plants not infected. Data are collected only whensufficient selection pressure exists in the experiment measured.

HSKCVR=HUSK COVER. A 1 to 9 score based on performance relative to keychecks, with a score of 1 indicating very short husks, tip of ear andkernels showing; 5 is intermediate coverage of the ear under mostconditions, sometimes with thin husk; and a 9 has husks extending andclosed beyond the tip of the ear. Scoring can best be done nearphysiological maturity stage or any time during dry down untilharvested.

HUSK EXTENSION: The distance the husk extends past the end of theprimary ear at harvest.

HUSK TIGHTNESS: The tightness of the husk 65 days after 50% silking on ascale from 1 (very loose) to 9 (very tight).

HYBRID VARIETY. A substantially heterozygous hybrid line and minorgenetic modifications thereof that retain the overall genetics of thehybrid line including but not limited to a locus conversion, a mutation,or a somoclonal variant.

INBRED. A variety developed through inbreeding or doubled haploidy thatpreferably comprises homozygous alleles at about 95% or more of itsloci.

INBRED VARIETY. A substantially homozygous inbred line and minormodifications thereof that retain the overall genetics of the inbredline including but not limited to a locus conversion, a mutation, or asomoclonal variant.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of variety to be patented over othervariety on per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. Gross income advantage of variety #1over variety #2.

INTERNODE: The structure between two nodes on the main stem.

INTROGRESSION. The process of transferring genetic material from onegenotype to another.

KERUNT=KERNELS PER UNIT AREA (Acres or Hectares).

KERPOP=KERNEL POP SCORE. The visual 1-9 rating of the amount ofrupturing of the kernel pericarp at an early stage in grain fill. Ahigher score is good and indicates no popped (ruptured) kernels.

KER WT=KERNEL NUMBER PER UNIT WEIGHT (Pounds or Kilograms). The numberof kernels in a specific measured weight; determined after removal ofextremely small and large kernels.

KSZDCD=KERNEL SIZE DISCARD. The percent of discard seed; calculated asthe sum of discarded tip kernels and extra large kernels.

LEAF ANGLE: The adaxial angle measured in degrees with a protractor onthe second leaf above the top ear at flowering.

LEAF SHEATH PUBESCENCE: The density of pubescence on the face of theleaf sheath at flowering. Leaf Sheath Pubescence is scored on a 1-9scale where 1=no pubescence (smooth) and 9=high level of pubescence(like peach fuzz).

LINKAGE. Refers to a phenomenon wherein alleles on the same chromosometend to segregate together more often than expected by chance if theirtransmission was independent.

LINKAGE DISEQUILIBRIUM. Refers to a phenomenon wherein alleles tend toremain together in linkage groups when segregating from parents tooffspring, with a greater frequency than expected from their individualfrequencies.

LOCUS. A specific location on a chromosome.

LOCUS CONVERSION. A locus conversion refers to plants within a varietythat have been modified in a manner that retains the overall genetics ofthe variety and further comprises one or more loci with a specificdesired trait, such as insect, disease or herbicide resistance.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1 to 9 relative system with a higher number indicatingthe variety responds well to low plant densities for yield relative toother varieties. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to low plant density.

LRTLDG=LATE ROOT LODGING. The percentage of plants that do not rootlodge after anthesis through harvest; plants that lean from the verticalaxis at an approximately 30 degree angle or greater would be counted asroot lodged. Data are collected only when sufficient selection pressureexists in the experiment measured.

LRTLPN=LATE ROOT LODGING. An estimate of the percentage of plants thatdo not root lodge after anthesis through harvest; plants that lean fromthe vertical axis at an approximately 30 degree angle or greater wouldbe considered as root lodged. Data are collected only when sufficientselection pressure exists in the experiment measured.

LRTLSC=LATE ROOT LODGING SCORE. Score for severity of plants that leanfrom a vertical axis at an approximate 30 degree angle or greater whichtypically results from strong winds after flowering. Recorded prior toharvest when a root-lodging event has occurred. This lodging results inplants that are leaned or “lodged” over at the base of the plant and donot straighten or “goose-neck” back to a vertical position. Expressed asa 1 to 9 score with 9 being no lodging. Data are collected only whensufficient selection pressure exists in the experiment measured.

MALE STERILITY. A male sterile plant is one which produces no viablepollen. Male sterility prevents self pollination and the pollination ofneighboring plants. These male sterile plants are therefore useful inhybrid plant production.

MDMCPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Complex. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MSTADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2—MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NEI DISTANCE. A quantitative measure of percent similarity between twovarieties. Nei's distance between varieties A and B can be defined as1−(2*number alleles in common/(number alleles in A+number alleles in B).For example, if lines A and B are the same for 95 out of 100 alleles,the Nei distance would be 0.05. If varieties A and B are the same for 98out of 100 alleles, the Nei distance would be 0.02. Free software forcalculating Nei distance is available on the internet at multiplelocations such as, for example, at:evolution.genetics.washington.edu/phylip.html. See Nei, Proc Natl AcadSci, 76:5269-5273 (1979) which is incorporated by reference for thispurpose.

NLFBLT=NORTHERN LEAF BLIGHT (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

NUCLEIC ACID. An acidic, chainlike biological macromolecule consistingof multiple repeat units of phosphoric acid, sugar and purine andpyrimidine bases.

OILT=GRAIN OIL. Absolute value of oil content of the kernel as predictedby Near-Infrared Transmittance and expressed as a percent of dry matter.

PEDIGREE DISTANCE. Relationship among generations based on theirancestral links as evidenced in pedigrees. May be measured by thedistance of the pedigree from a given starting point in the ancestry.

PEDUNCLE NODE: The node on the main stem that the tassel originatesfrom.

PERCENT IDENTITY. Percent identity as used herein refers to thecomparison of the alleles of two plants or varieties as scored bymatching loci. Percent identity is determined by comparing astatistically significant number of the loci of two plants or varietiesand scoring a match when the same two alleles are present at the sameloci for each plant. For example, a percent identity of 90% betweenmaize variety X6N745 and another plant means that the two plants havethe same two alleles at 90% of their loci.

PERCENT SIMILARITY. Percent similarity as used herein refers to thecomparison of the alleles of two plants or varieties as scored bymatching alleles. Percent similarity is determined by comparing astatistically significant number of the loci of two plants or varietiesand scoring one allele match when the same allele is present at the sameloci for each plant and two allele matches when the same two alleles arepresent at the same loci for each plant. A percent similarity of 90%between maize variety X6N745 and another plant means that the two plantshave 90% matching alleles.

PLANT. As used herein, the term “plant” includes reference to animmature or mature whole plant, including a plant that has beendetasseled or from which seed or grain has been removed. Seed or embryothat will produce the plant is also considered to be the plant.

PLANT PARTS. As used herein, the term “plant parts” includes leaves,stems, roots, seed, grain, embryo, pollen, ovules, flowers, ears, cobs,husks, stalks, root tips, anthers, pericarp, silk, tissue, cells and thelike.

PLTHT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in centimeters.

POLPRD=POLLEN PRODUCTION SCORE. The estimated total amount of pollenproduced by tassels based on the number of tassel branches and thedensity of the spikelets.

POLSC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POLWT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

POP K/A=PLANT POPULATIONS. Measured as 1000's per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2—PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety#1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is also referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRMSHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

PRIMARY LATERAL TASSEL BRANCH: A branch that originates off the mainaxis of the tassel with more than 2 florets.

PROT=GRAIN PROTEIN. Absolute value of protein content of the kernel aspredicted by Near-Infrared Transmittance and expressed as a percent ofdry matter.

RESISTANCE. Synonymous with tolerance. The ability of a plant towithstand exposure to an insect, disease, herbicide or other condition.A resistant plant variety will have a level of resistance higher than acomparable wild-type variety.

RTLDG=ROOT LODGING. Root lodging is the percentage of plants that do notroot lodge; plants that lean from the vertical axis at an approximately30 degree angle or greater would be counted as root lodged. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

RTLADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2. Data are collected only when sufficient selectionpressure exists in the experiment measured.

SCTGRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDGVGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEED. Fertilized and ripened ovule, consisting of the plant embryo,varying amounts of stored food material, and a protective outer seedcoat. Synonymous with grain.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe maize variety's worth based on information for multiple traits. Amaize breeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SIL DMP=SILAGE DRY MATTER. The percent of dry material in chopped wholeplant silage.

SELF POLLINATION. A plant is self-pollinated if pollen from one floweris transferred to the same or another flower of the same plant.

SIB POLLINATION. A plant is sib-pollinated when individuals within thesame family or variety are used for pollination.

SINGLE LOCUS CONVERSION TRAIT. A trait that can be introgressed into acorn variety through introgression and/or transformation of a singlelocus.

Examples of such single locus traits include mutant genes, transgenesand native traits finely mapped to a single locus. One or more singlelocus conversion traits may be introduced into a single corn variety.

SITE SPECIFIC INTEGRATION. Genes that create a site for site specificDNA integration. This includes the introduction of FRT sites that may beused in the FLP/FRT system and/or Lox sites that may be used in theCre/Loxp system. For example, see Lyznik, et al., Site-SpecificRecombination for Genetic Engineering in Plants, Plant Cell Rep (2003)21:925-932 and WO 99/25821.

SLFBLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

SOURST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

SPKDSC=SPIKLET DENSITY SCORE. The visual 1-9 rating of how densespikelets are on the middle tassel branches. A higher score indicateshigher spikelet density.

STAGRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STARCH=PERCENT OF STARCH. The percent of dry matter that is starch inchopped whole plant forage.

STDADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STKCNT=NUMBER OF PLANTS. This is the final stand or number of plants perplot.

STKLDG=STALK LODGING REGULAR. This is the percentage of plants that didnot stalk lodge (stalk breakage) at regular harvest (when grain moistureis between about 20 and 30%) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear. Data are collected only when sufficient selectionpressure exists in the experiment measured.

STKLDS=STALK LODGING SCORE. A plant is considered as stalk lodged if thestalk is broken or crimped between the ear and the ground. This can becaused by any or a combination of the following: strong winds late inthe season, disease pressure within the stalks, ECB damage orgenetically weak stalks. This trait should be taken just prior to or atharvest. Expressed on a 1 to 9 scale with 9 being no lodging. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

STLLPN=LATE STALK LODGING. This is the percent of plants that did notstalk lodge (stalk breakage or crimping) at or around late seasonharvest (when grain moisture is below 20%) as measured by either naturallodging or pushing the stalks and determining the percentage of plantsthat break or crimp below the ear. Data are collected only whensufficient selection pressure exists in the experiment measured.

STLPCN=STALK LODGING REGULAR. This is an estimate of the percentage ofplants that did not stalk lodge (stalk breakage) at regular harvest(when grain moisture is between about 20 and 30%) as measured by eithernatural lodging or pushing the stalks and determining the percentage ofplants that break below the ear. Data are collected only when sufficientselection pressure exists in the experiment measured.

STLTIP=STERILE TIPS SCORE. The visual 1 to 9 rating of the relative lackof glumes on the tassel central spike and branches. A higher scoreindicates less incidence of sterile tips or lack of glumes on thetassel.

STRT=GRAIN STARCH. Absolute value of starch content of the kernel aspredicted by Near-Infrared Transmittance and expressed as a percent ofdry matter.

STWWLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

SSRs. Genetic markers based on polymorphisms in repeated nucleotidesequences, such as microsatellites. A marker system based on SSRs can behighly informative in linkage analysis relative to other marker systemsin that multiple alleles may be present.

TASBLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

TASBRN=TASSEL BRANCH NUMBER. The number of tassel branches, with anthersoriginating from the central spike.

TASSZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TDM/HA=TOTAL DRY MATTER PER HECTARE. Yield of total dry plant materialin metric tons per hectare.

TEXEAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data are given as a percentage oftillers: number of tillers per plot divided by number of plants perplot. A tiller is defined as a secondary shoot that has developed as atassel capable of shedding pollen.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin kilograms for a given volume (cubic meter).

TSWADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

TOP EAR: The highest and primary seed bearing structure of the cornplant.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YIELD BU/A=YIELD (BUSHELS/ACRE). Yield of the grain at harvest inbushels per acre adjusted to 15% moisture.

YLDADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1—YIELD variety #2=YIELDADVANTAGE of variety #1.

YLDSC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

Definitions for Area of Adaptability

When referring to area of adaptability, such term is used to describethe location with the environmental conditions that would be well suitedfor this maize variety. Area of adaptability is based on a number offactors, for example: days to maturity, insect resistance, diseaseresistance, and drought resistance. Area of adaptability does notindicate that the maize variety will grow in every location within thearea of adaptability or that it will not grow outside the area.

Central Corn Belt: Iowa, Illinois, Indiana

Drylands: non-irrigated areas of North Dakota, South Dakota, Nebraska,Kansas, Colorado and Oklahoma

Eastern U.S.: Ohio, Pennsylvania, Delaware, Maryland, Virginia, and WestVirginia

North central U.S.: Minnesota and Wisconsin

Northeast: Michigan, New York, Vermont, and Ontario and Quebec Canada

Northwest U.S.: North Dakota, South Dakota, Wyoming, Washington, Oregon,Montana, Utah, and Idaho

South central U.S.: Missouri, Tennessee, Kentucky, Arkansas

Southeast U.S.: North Carolina, South Carolina, Georgia, Florida,Alabama, Mississippi, and Louisiana

Southwest U.S.: Texas, Oklahoma, New Mexico, Arizona

Western U.S.: Nebraska, Kansas, Colorado, and California

Maritime Europe Northern France, Germany, Belgium, Netherlands andAustria

DETAILED DESCRIPTION OF THE INVENTION AND FURTHER EMBODIMENTS

All tables discussed in the Detailed Description of the Invention andFurther Embodiments section can be found at the end of the section.

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is sib pollinated when individuals within the same familyor line are used for pollination. A plant is cross-pollinated if thepollen comes from a flower on a different plant from a different familyor line.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of heterogeneous plants that differ genetically and will notbe uniform.

Maize (Zea mays L.), often referred to as corn in the United States, canbe bred by both self-pollination and cross-pollination techniques. Maizehas separate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

There are many important factors to be considered in the art of plantbreeding, such as the ability to recognize important morphological andphysiological characteristics, the ability to design evaluationtechniques for genotypic and phenotypic traits of interest, and theability to search out and exploit the genes for the desired traits innew or improved combinations.

One objective of commercial maize variety development is to develop newinbred varieties to produce hybrids that combine to produce high grainyields and superior agronomic performance. One of the primary traitsbreeders seek is yield.

However, many other major agronomic traits are of importance in hybridcombination and have an impact on yield or otherwise provide superiorperformance in hybrid combinations. Such traits include percent grainmoisture at harvest, relative maturity, resistance to stalk breakage,resistance to root lodging, grain quality, and disease and insectresistance.

The utility of maize variety X6N745 also extends to crosses with otherspecies. Commonly, suitable species will be of the family Graminaceae,and especially of the genera Zea, Tripsacum, Coix, Schlerachne,Polytoca, Chionachne, and Trilobachne, of the tribe Maydeae. Potentiallysuitable for crosses with X6N745 may be the various varieties of grainsorghum, Sorghum bicolor (L.) Moench.

Morphological and Physiological Characteristics of X6N745

Pioneer brand hybrid X6N745 is characterized by excellent grain yieldand good silage tonnage. Stalk strength is good for this hybrid withmoderate plant and ear height. Tolerance to Goss's wilt is excellent asis emergence in the spring under stress. This hybrid has good toleranceto northern leaf blight and Gibberella ear mold. The maize variety isparticularly suited to the Northeast.

Pioneer Brand Maize Variety X6N745 is a single cross, yellow endospermmaize variety. Maize Variety X6N745 has a relative maturity ofapproximately 98 based on the Comparative Relative Maturity RatingSystem for harvest moisture of grain.

The maize variety has shown uniformity and stability within the limitsof environmental influence for all the traits as described in theVariety Description Information (Table 1, found at the end of thesection). The inbred parents of this maize variety have beenself-pollinated and ear-rowed a sufficient number of generations withcareful attention paid to uniformity of plant type to ensure thehomozygosity and phenotypic stability necessary for use in commercialhybrid seed production. The variety has been increased both by hand andin isolated fields with continued observation for uniformity. No varianttraits have been observed or are expected in X6N745.

Maize variety X6N745 can be reproduced by planting seeds of the inbredparent varieties, growing the resulting maize plants under crosspollinating conditions, and harvesting the resulting seed usingtechniques familiar to the agricultural arts.

Genotypic Characteristics of X6N745

In addition to phenotypic observations, a plant can also be described byits genotype. The genotype of a plant can be characterized through agenetic marker profile which can identify plants of the same variety ora related variety or be used to determine or validate a pedigree. Forexample, the genotype can be used to determine the pedigree of a plant.There are many laboratory-based techniques available for the analysis,comparison and characterization of plant genotype; among these areIsozyme Electrophoresis, Restriction Fragment Length Polymorphisms(RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily PrimedPolymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting(DAF), Sequence Characterized Amplified Regions (SCARs), AmplifiedFragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs)which are also referred to as Microsatellites, and Single NucleotidePolymorphisms (SNPs). For example, see Berry, Don, et al., “AssessingProbability of Ancestry Using Simple Sequence Repeat Profiles:Applications to Maize Hybrids and Inbreds”, Genetics, 2002, 161:813-824, and Berry, Don et al., “Assessing Probability of Ancestry UsingSimple Sequence Repeat Profiles: Applications to Maize Inbred Lines andSoybean Varieties”, Genetics, 2003, 165: 331-342, which are incorporatedby reference herein in their entirety.

Particular markers used for these purposes may include any type ofmarker and marker profile which provides a means of distinguishingvarieties. In addition to being used for identification of inbredparents, maize variety X6N745, a maize variety produced through the useof X6N745 or its parents, and the identification or verification ofpedigree for progeny plants produced through the use of X6N745, thegenetic marker profile is also useful in developing an introgressedtrait conversion of X6N745.

Means of performing genetic marker profiles using SSR polymorphisms arewell known in the art. SSRs are genetic markers based on polymorphismsin repeated nucleotide sequences, such as microsatellites. A markersystem based on SSRs can be highly informative in linkage analysisrelative to other marker systems in that multiple alleles may bepresent. Another advantage of this type of marker is that, through useof flanking primers, detection of SSRs can be achieved, for example, bythe polymerase chain reaction (PCR), thereby eliminating the need forlabor-intensive Southern hybridization. The PCR™ detection is done byuse of two oligonucleotide primers flanking the polymorphic segment ofrepetitive DNA. Repeated cycles of heat denaturation of the DNA followedby annealing of the primers to their complementary sequences at lowtemperatures, and extension of the annealed primers with DNA polymerase,comprise the major part of the methodology.

Following amplification, markers can be scored by gel electrophoresis ofthe amplification products. Scoring of marker genotype is based on thesize of the amplified fragment, which may be measured by the base pairweight or molecular weight of the fragment. While variation in theprimer used or in laboratory procedures can affect the reportedmolecular weight, relative values should remain constant regardless ofthe specific primer or laboratory used. When comparing plants it ispreferable if all SSR profiles are performed in the same lab. An SSRservice is available to the public on a contractual basis by DNALandmarks in Saint-Jean-sur-Richelieu, Quebec, Canada.

Primers used for SSRs are publicly available and may be found in theMaize GDB on the World Wide Web at maizegdb.org (sponsored by the USDAAgricultural Research Service), in Sharopova et al. (Plant Mol. Biol.48(5-6):463-481), Lee et al. (Plant Mol. Biol. 48(5-6); 453-461).Primers may be constructed from publicly available sequence information.Some marker information may be available from DNA Landmarks.

The scope of the invention includes use of methods, for example, IsozymeElectrophoresis, Restriction Fragment Length Polymorphisms (RFLPs),Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily PrimedPolymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting(DAF), Sequence Characterized Amplified Regions (SCARs), AmplifiedFragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs),and Single Nucleotide Polymorphisms (SNPs), with transgenic or backcrossconversions of maize variety X6N745. One such embodiment is a method ofdeveloping a variety genetically similar to maize variety X6N745 inbreeding that involves the repeated backcrossing of an inbred parent of,or a double haploid inbred variety derived from, maize variety X6N745.

Comparisons for Pioneer Maize X6N745

A breeder uses various methods to help determine which plants should beselected from segregating populations and ultimately which inbredvarieties will be used to develop hybrids for commercialization. Inaddition to knowledge of the germplasm and plant genetics, a part of theselection process is dependent on experimental design coupled with theuse of statistical analysis. Experimental design and statisticalanalysis are used to help determine which plants, which family ofplants, and finally which inbred varieties and hybrid combinations aresignificantly better or different for one or more traits of interest.Experimental design methods are used to assess error so that differencesbetween two inbred varieties or two hybrid varieties can be moreaccurately evaluated. Statistical analysis includes the calculation ofmean values, determination of the statistical significance of thesources of variation, and the calculation of the appropriate variancecomponents. One of ordinary skill in the art of plant breeding wouldknow how to evaluate the traits of two plant varieties to determine ifthere is no significant difference between the two traits expressed bythose varieties. For example, see Fehr, Walt, Principles of CultivarDevelopment, pages 261-286 (1987). Mean trait values may be used todetermine whether trait differences are significant. Trait values shouldpreferably be measured on plants grown under the same environmentalconditions, and environmental conditions should be appropriate for thetraits or traits being evaluated. Sufficient selection pressure shouldbe present for optimum measurement of traits of interest such asherbicide, insect or disease resistance. A locus conversion of X6N745for herbicide resistance should be compared with an isogenic counterpartin the absence of the converted trait. In addition, a locus conversionfor insect or disease resistance should be compared to the isogeniccounterpart, in the absence of disease pressure or insect pressure.

In Table 2 (Table 2, found at the end of the section), data from traitsand characteristics of maize variety X6N745 per se are given andcompared to other maize varieties. The following are the results ofthese comparisons. The results in Table 2 show maize variety X6N745 hassignificantly different traits compared to other maize varieties.

Comparisons of characteristics for Pioneer Brand Maize Variety X6N745were made against Maize Varieties 36W66, 37F73, 37V63 and 37N68.

Table 2A compares Pioneer Brand Maize Variety X6N745 and Maize Variety36W66, a variety with a similar area of adaptation. The results showMaize Variety X6N745 has significantly different test weight andmoisture compared to Maize Variety 36W66.

Table 2B compares Pioneer Brand Maize Variety X6N745 and Maize Variety37F73, a maize variety with a similar area of adaptation. The resultsshow Maize Variety X6N745 differs significantly over multiple traitsincluding growing degree units to silk and husk cover when compared toMaize Variety 37F73.

Table 2C compares Pioneer Brand Maize Variety X6N745 and Maize Variety37V63, a maize variety with a similar area of adaptation. The resultsshow Maize Variety X6N745 differs significantly from Variety 37V63 in anumber of traits including yield and plant height.

Table 2D compares Pioneer Brand Maize Variety X6N745 and Maize Variety37N68, a maize variety with a similar area of adaptation. The resultsshow Maize Variety X6N745 differs significantly from Maize Variety 37N68in a number of traits including yield and husk cover.

Development of Maize Hybrids using X6N745

During the inbreeding process in maize, the vigor of the varietiesdecreases. However, vigor is restored when two different inbredvarieties are crossed to produce the hybrid progeny (F1). An importantconsequence of the homozygosity and homogeneity of the inbred varietiesis that the hybrid between a defined pair of inbreds may be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained. Once the inbreds that create a superior hybrid have beenidentified, a continual supply of the hybrid seed can be produced usingthese inbred parents and the hybrid corn plants can then be generatedfrom this hybrid seed supply.

One method of developing a maize hybrid in a maize plant breedingprogram involves three steps: (1) the selection of plants from variousgermplasm pools for initial breeding crosses; (2) the selfing of theselected plants from the breeding crosses for several generations toproduce a series of inbred varieties, which, individually breed true andare highly uniform; and (3) crossing a selected inbred variety with anunrelated inbred variety to produce the hybrid progeny (F1). After asufficient amount of inbreeding successive filial generations willmerely serve to increase seed of the developed inbred.

X6N745 may be used to produce a double cross hybrid or a three-wayhybrid. A single cross hybrid is produced when two inbred varieties arecrossed to produce the F1 progeny. A double cross hybrid is producedfrom four inbred varieties crossed in pairs (A×B and C×D) and then thetwo F1 hybrids are crossed again (A×B)×(C×D). A three-way cross hybridis produced from three inbred varieties where two of the inbredvarieties are crossed (A×B) and then the resulting F1 hybrid is crossedwith the third inbred variety (A×B)×C. In each case, pericarp tissuefrom the female parent will be a part of and protect the hybrid seed.

Hybrid seed production requires elimination or inactivation of pollenproduced by the female parent. Incomplete removal or inactivation of thepollen provides the potential for self-pollination. This inadvertentlyself-pollinated seed may be unintentionally harvested and packaged withhybrid seed. Also, because the male parent plant is grown in rows, thatare typically destroyed prior to seed development, next to the femaleparent in the field there is the very low probability that the maleselfed seed could be unintentionally harvested and packaged with thehybrid seed. Once the seed from the hybrid bag is planted, it ispossible to identify and select these self-pollinated plants. Theseself-pollinated plants will be one of the inbred varieties or F1's usedto produce the hybrid. Though the possibility of selfs being included ina hybrid seed bag exists, the occurrence is very low because much careis taken by seed companies to avoid such inclusions. It is worth notingthat hybrid seed is sold to growers for the production of grain andforage and not for breeding or seed production. By an individual skilledin plant breeding, these selfed plants unintentionally included incommercial hybrid seed can be identified and selected. Inbreds areidentified by their less vigorous appearance for vegetative and/orreproductive characteristics, including shorter plant height, small earsize, ear and kernel shape, cob color, or other characteristics.

Identification of these self-pollinated varieties can also beaccomplished through molecular marker analyses. See “The Identificationof Female Selfs in Hybrid Maize: A Comparison Using Electrophoresis andMorphology”, Smith, J. S. C. and Wych, R. D., Seed Science andTechnology 14, pages 1-8 (1995), the disclosure of which is expresslyincorporated herein by reference. Through these technologies, thehomozygosity of the self pollinated variety can be verified by analyzingallelic composition at various loci along the genome. Those methodsallow for rapid identification of the invention disclosed herein. Seealso, “Identification of Atypical Plants in Hybrid Maize Seed byPostcontrol and Electrophoresis” Sarca, V. et al., Probleme de GeneticaTeoritica si Aplicata Vol. (1) pages 29-42.

Another form of commercial hybrid production involves the use of amixture of male sterile hybrid seed and male pollinator seed. Whenplanted, the resulting male sterile hybrid plants are pollinated by thepollinator plants. This method is primarily used to produce grain withenhanced quality grain traits, such as high oil, because desired qualitygrain traits expressed in the pollinator will also be expressed in thegrain produced on the male sterile hybrid plant. In this method thedesired quality grain trait does not have to be incorporated by lengthyprocedures such as recurrent backcross selection into an inbred parentline. One use of this method is described in U.S. Pat. Nos. 5,704,160and 5,706,603.

Introgression of a New Locus or Trait into X6N745

X6N745 represents a new base genetic line into which a new locus ortrait may be introduced. Direct transformation and backcrossingrepresent two important methods that can be used to accomplish such anintrogression. The term locus conversion is used to designate theproduct of such an introgression.

To select and develop a superior hybrid, it is necessary to identify andselect genetically unique individuals that occur in a segregatingpopulation. The segregating population is the result of a combination ofcrossover events plus the independent assortment of specificcombinations of alleles at many gene loci that results in specific andunique genotypes. Once such a variety is developed its value to societyis substantial since it is important to advance the germplasm base as awhole in order to maintain or improve traits such as yield, diseaseresistance, pest resistance and plant performance in extreme weatherconditions. Backcross trait conversions are routinely used to add ormodify one or a few traits of such a line and this further enhances itsvalue and usefulness to society. The genetic variation among individualprogeny of a breeding cross allows for the identification of rare andvaluable new genotypes. Once identified, it is possible to utilizeroutine and predictable breeding methods to develop progeny that retainthe rare and valuable new genotypes developed by the initial breeder.

Backcrossing can be used to improve inbred varieties and a hybridvariety which is made using those inbreds. Backcrossing can be used totransfer a specific desirable trait from one variety, the donor parent,to an inbred called the recurrent parent which has overall goodagronomic characteristics yet that lacks the desirable trait. Thistransfer of the desirable trait into an inbred with overall goodagronomic characteristics can be accomplished by first crossing arecurrent parent to a donor parent (non-recurrent parent). The progenyof this cross is then mated back to the recurrent parent followed byselection in the resultant progeny for the desired trait to betransferred from the non-recurrent parent.

Traits may be used by those of ordinary skill in the art to characterizeprogeny. Traits are commonly evaluated at a significance level, such asa 1%, 5% or 10% significance level, when measured in plants grown in thesame environmental conditions. For example, a backcross conversion ofX6N745 may be characterized as having the same morphological andphysiological traits as X6N745. The traits used for comparison may bethose traits shown in Table 1 or Table 2. Molecular markers can also beused during the breeding process for the selection of qualitativetraits. For example, markers closely linked to alleles or markerscontaining sequences within the actual alleles of interest can be usedto select plants that contain the alleles of interest during abackcrossing breeding program. The markers can also be used to selectfor the genome of the recurrent parent and against the genome of thedonor parent. Using this procedure can minimize the amount of genomefrom the donor parent that remains in the selected plants.

A locus conversion of X6N745 will retain the genetic integrity ofX6N745. A locus conversion of X6N745 will comprise at least 92%, 93%,94%, 95%, 96%, 97%, 98% or 99% of the base genetics of X6N745. Forexample, a locus conversion of X6N745 can be developed when DNAsequences are introduced through backcrossing (Hallauer et al., 1988),with a parent of X6N745 utilized as the recurrent parent. Both naturallyoccurring and transgenic DNA sequences may be introduced throughbackcrossing techniques. A backcross conversion may produce a plant witha trait or locus conversion in at least one or more backcrosses,including at least 2 crosses, at least 3 crosses, at least 4 crosses, atleast 5 crosses and the like. Molecular marker assisted breeding orselection may be utilized to reduce the number of backcrosses necessaryto achieve the backcross conversion. For example, see Openshaw, S. J. etal., Marker-assisted Selection in Backcross Breeding. In: ProceedingsSymposium of the Analysis of Molecular Data, August 1994, Crop ScienceSociety of America, Corvallis, Oreg., where it is demonstrated that abackcross conversion can be made in as few as two backcrosses.

The complexity of the backcross conversion method depends on the type oftrait being transferred (single genes or closely linked genes as vs.unlinked genes), the level of expression of the trait, the type ofinheritance (cytoplasmic or nuclear) and the types of parents includedin the cross. It is understood by those of ordinary skill in the artthat for single gene traits that are relatively easy to classify, thebackcross method is effective and relatively easy to manage. (SeeHallauer et al. in Corn and Corn Improvement, Sprague and Dudley, ThirdEd. 1998). Desired traits that may be transferred through single locustrait conversion include, but are not limited to, waxy starch, sterility(nuclear and cytoplasmic), fertility restoration, grain color (white),drought resistance enhanced nitrogen utilization efficiency, alterednitrogen responsiveness, altered fatty acid profile, disease resistance(bacterial, fungal or viral), insect resistance, herbicide resistanceand yield enhancements. In addition, an introgression site itself, suchas an FRT site, Lox site or other site specific integration site, may beinserted by backcrossing and utilized for direct insertion of one ormore genes of interest into a specific plant variety. The trait ofinterest is transferred from the donor parent to the recurrent parent,in this case, an inbred parent of the maize variety disclosed herein.The seed industry commonly markets “triple stacks” of base genetics;which can be varieties comprising a locus conversion of at least 3 loci.Similarly, “quadruple stacks” would comprise the base genetics and couldcomprise a locus conversion of at least 4 loci. The seed industrycommonly markets “triple stacks” of base genetics; which can bevarieties comprising a locus conversion of at least 3 loci. Similarly,“quadruple stacks” would comprise the base genetics and could comprise alocus conversion of at least 4 loci. Stacking of traits is common tothose of ordinary skill in the art of plant breeding and stacked traitsaccount for a significant percentage of commercial corn hybrid sales.For example, figures from Purdue University show that biotech-trait cornaccounted for 61% of all corn acres in 2006 and corn with two or morestacked traits accounted for 11.9 million acres. That's a significantportion of the approximately 80 million acres of corn grown in theUnited States. In addition, for 2007 at least one company projectsselling more triple-stack corn hybrids than single trait hybrids. (WayneWenzel, “Double, Triple, Quad”, published Nov. 8, 2006, Agweb.com,accessed Dec. 4, 2006). A single locus may contain several transgenes,such as a transgene for disease resistance that, in the same expressionvector, also contains a transgene for herbicide resistance. The gene forherbicide resistance may be used as a selectable marker and/or as aphenotypic trait. A locus trait conversion of a site specificintegration system allows for the integration of multiple genes at theconverted loci. Further, SSI and FRT technologies known to those ofskill in the art in the art may result in multiple gene introgressionsat a single locus.

The locus conversion may result from either the transfer of a dominantallele or a recessive allele. Selection of progeny containing the traitof interest is accomplished by direct selection for a trait associatedwith a dominant allele. Transgenes transferred via backcrossingtypically function as a dominant single gene trait and are relativelyeasy to classify. Selection of progeny for a trait that is transferredvia a recessive allele, such as the waxy starch characteristic, requiresgrowing and selfing the first backcross generation to determine whichplants carry the recessive alleles. Recessive traits may requireadditional progeny testing in successive backcross generations todetermine the presence of the locus of interest. The last backcrossgeneration is usually selfed to give pure breeding progeny for thegene(s) being transferred, although a backcross conversion with a stablyintrogressed trait may also be maintained by further backcrossing to therecurrent parent with selection for the converted trait.

Along with selection for the trait of interest, progeny are selected forthe phenotype and/or genotype of the recurrent parent. Whileoccasionally additional polynucleotide sequences or genes may betransferred along with the backcross conversion, the backcrossconversion variety “fits into the same hybrid combination as therecurrent parent inbred variety and contributes the effect of theadditional gene added through the backcross.” See Poehlman et al. (1995,page 334). It has been proposed that in general there should be at leastfour backcrosses when it is important that the recovered varieties beessentially identical to the recurrent parent except for thecharacteristic being transferred (Fehr 1987, Principles of CultivarDevelopment). However, as noted above, the number of backcrossesnecessary can be reduced with the use of molecular markers. Otherfactors, such as a genetically similar donor parent, may also reduce thenumber of backcrosses necessary.

Male Sterility and Hybrid Seed Production

Hybrid seed production requires elimination or inactivation of pollenproduced by the female inbred parent. Incomplete removal or inactivationof the pollen provides the potential for self-pollination. A reliablemethod of controlling male fertility in plants offers the opportunityfor improved seed production. There are several ways in which a maizeplant can be manipulated so that it is male sterile. These include useof manual or mechanical emasculation (or detasseling), use of one ormore genetic factors that confer male sterility, including cytoplasmicgenetic and/or nuclear genetic male sterility, use of gametocides andthe like. All of such embodiments are within the scope of the presentclaims. The term manipulated to be male sterile refers to the use of anyavailable techniques to produce a male sterile version of maize varietyX6N745. The male sterility may be either partial or complete malesterility.

Hybrid maize seed is often produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twoinbred varieties of maize are planted in a field, and the pollen-bearingtassels are removed from one of the inbreds (female) prior to pollenshed. Providing that there is sufficient isolation from sources offoreign maize pollen, the ears of the detasseled inbred will befertilized only from the other inbred (male), and the resulting seed istherefore hybrid and will form hybrid plants.

Large scale commercial maize hybrid production, as it is practicedtoday, requires the use of some form of male sterility system whichcontrols or inactivates male fertility. A reliable method of controllingmale fertility in plants also offers the opportunity for improved plantbreeding. This is especially true for development of maize hybrids,which relies upon some sort of male sterility system. There are severalways in which a maize plant can be manipulated so that is male sterile.These include use of manual or mechanical emasculation (or detasseling),cytoplasmic genetic male sterility, nuclear genetic male sterility,gametocides and the like.

The laborious detasseling process can be avoided by using cytoplasmicmale-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile as aresult of genetic factors in the cytoplasm, as opposed to the nucleus,and so nuclear linked genes are not transferred during backcrossing.Thus, this characteristic is inherited exclusively through the femaleparent in maize plants, since only the female provides cytoplasm to thefertilized seed. CMS plants are fertilized with pollen from anotherinbred that is not male-sterile. Pollen from the second inbred may ormay not contribute genes that make the hybrid plants male-fertile, andeither option may be preferred depending on the intended use of thehybrid. The same hybrid seed, a portion produced from detasseled fertilemaize and a portion produced using the CMS system can be blended toinsure that adequate pollen loads are available for fertilization whenthe hybrid plants are grown. CMS systems have been successfully usedsince the 1950's, and the male sterility trait is routinely backcrossedinto inbred varieties. See Wych, p. 585-586, 1998.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. Pat. No.5,432,068, describe a system of nuclear male sterility which includes:identifying a gene which is critical to male fertility; silencing thisnative gene which is critical to male fertility; removing the nativepromoter from the essential male fertility gene and replacing it with aninducible promoter; inserting this genetically engineered gene back intothe plant; and thus creating a plant that is male sterile because theinducible promoter is not “on” resulting in the male fertility gene notbeing transcribed. Fertility is restored by inducing, or turning “on”,the promoter, which in turn allows the gene that confers male fertilityto be transcribed.

These, and the other methods of conferring genetic male sterility in theart, each possess their own benefits and drawbacks. Some other methodsuse a variety of approaches such as delivering into the plant a geneencoding a cytotoxic substance associated with a male tissue specificpromoter or an antisense system in which a gene critical to fertility isidentified and an antisense to that gene is inserted in the plant (seeFabinjanski, et al. EPO 89/3010153.8 Publication No. 329,308 and PCTApplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach and it is not appropriate in allsituations.

Transformation

The advent of new molecular biological techniques has allowed theisolation and characterization of genetic elements with specificfunctions, such as encoding specific protein products. Scientists in thefield of plant biology developed a strong interest in engineering thegenome of plants to contain and express foreign genetic elements, oradditional, or modified versions of native or endogenous geneticelements in order to alter the traits of a plant in a specific manner.Any DNA sequences, whether from a different species or from the samespecies, which are inserted into the genome using transformation arereferred to herein collectively as “transgenes”. Over the last fifteento twenty years several methods for producing transgenic plants havebeen developed, and the present invention also relates to transformedversions of the claimed maize variety X6N745 as well as combinationsthereof.

Numerous methods for plant transformation have been developed, includingbiological and physical plant transformation protocols. See, forexample, Miki et al., “Procedures for Introducing Foreign DNA intoPlants” in Methods in Plant Molecular Biology and Biotechnology, Glick,B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages67-88 and Armstrong, “The First Decade of Maize Transformation: A Reviewand Future Perspective” (Maydica 44:101-109, 1999). In addition,expression vectors and in vitro culture methods for plant cell or tissuetransformation and regeneration of plants are available. See, forexample, Gruber et al., “Vectors for Plant Transformation” in Methods inPlant Molecular Biology and Biotechnology, Glick, B. R. and Thompson, J.E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 89-119.

The most prevalent types of plant transformation involve theconstruction of an expression vector. Such a vector comprises a DNAsequence that contains a gene under the control of or operatively linkedto a regulatory element, for example a promoter. The vector may containone or more genes and one or more regulatory elements.

A genetic trait which has been engineered into the genome of aparticular maize plant using transformation techniques, could be movedinto the genome of another variety using traditional breeding techniquesthat are well known in the plant breeding arts. These varieties can thenbe crossed to generate a maize variety plant such as maize variety plantX6N745 which comprises a transgene. For example, a backcrossing approachis commonly used to move a transgene from a transformed maize plant toan elite inbred variety, and the resulting progeny would then comprisethe transgene(s). Also, if an inbred variety was used for thetransformation then the transgenic plants could be crossed to adifferent inbred in order to produce a transgenic hybrid maize plant.

Various genetic elements can be introduced into the plant genome usingtransformation. These elements include, but are not limited to genes;coding sequences; inducible, constitutive, and tissue specificpromoters; enhancing sequences; and signal and targeting sequences. Forexample, see the traits, genes and transformation methods listed in U.S.Pat. Nos. 6,118,055 and 6,284,953, which are herein incorporated byreference. In addition, transformability of a variety can be increasedby introgressing the trait of high transformability from another varietyknown to have high transformability, such as Hi-II. See U.S. PatentApplication Publication No. 2004/0016030.

With transgenic plants according to the present invention, a foreignprotein can be produced in commercial quantities. Thus, techniques forthe selection and propagation of transformed plants, which are wellunderstood in the art, yield a plurality of transgenic plants that areharvested in a conventional manner, and a foreign protein then can beextracted from a tissue of interest or from total biomass. Proteinextraction from plant biomass can be accomplished by known methods whichare discussed, for example, by Heney and Orr, Anal. Biochem. 114: 92-6(1981).

Transgenes can be mapped by one of ordinary skill in the art and suchtechniques are well known to those of ordinary skill in the art. Forexemplary methodologies in this regard, see for example, Glick andThompson, Methods In Plant Molecular Biology And Biotechnology, 269-284(CRC Press, Boca Raton, 1993).

Likewise, by means of the present invention, plants can be geneticallyengineered to express various phenotypes of agronomic interest. Throughthe transformation of maize the expression of genes can be altered toenhance disease resistance, insect resistance, herbicide resistance,agronomic traits, grain quality and other traits. Transformation canalso be used to insert DNA sequences which control or help controlmale-sterility. DNA sequences native to maize as well as non-native DNAsequences can be transformed into maize and used to alter levels ofnative or non-native proteins. Various promoters, targeting sequences,enhancing sequences, and other DNA sequences can be inserted into themaize genome for the purpose of altering the expression of proteins.Reduction of the activity of specific genes (also known as genesilencing, or gene suppression) is desirable for several aspects ofgenetic engineering in plants.

Many techniques for gene silencing are well known to one of skill in theart, including but not limited to knock-outs (such as by insertion of atransposable element such as mu (Vicki Chandler, The Maize Handbook ch.118 (Springer-Verlag 1994) or other genetic elements such as a FRT, Loxor other site specific integration site, antisense technology (see,e.g., Sheehy et al. (1988) PNAS USA 85:8805-8809; and U.S. Pat. Nos.5,107,065; 5,453,566; and 5,759,829); co-suppression (e.g., Taylor(1997) Plant Cell 9:1245; Jorgensen (1990) Trends Biotech.8(12):340-344; Flavell (1994) PNAS USA 91:3490-3496; Finnegan et al.(1994) Bio/Technology 12: 883-888; and Neuhuber et al. (1994) Mol. Gen.Genet. 244:230-241); RNA interference (Napoli et al. (1990) Plant Cell2:279-289; U.S. Pat. No. 5,034,323; Sharp (1999) Genes Dev. 13:139-141;Zamore et al. (2000) Cell 101:25-33; and Montgomery et al. (1998) PNASUSA 95:15502-15507), virus-induced gene silencing (Burton, et al. (2000)Plant Cell 12:691-705; and Baulcombe (1999) Curr. Op. Plant Bio.2:109-113); target-RNA-specific ribozymes (Haseloff et al. (1988) Nature334: 585-591); hairpin structures (Smith et al. (2000) Nature407:319-320; WO 99/53050; and WO 98/53083); MicroRNA (Aukerman & Sakai(2003) Plant Cell 15:2730-2741); ribozymes (Steinecke et al. (1992) EMBOJ. 11:1525; and Perriman et al. (1993) Antisense Res. Dev. 3:253);oligonucleotide mediated targeted modification (e.g., WO 03/076574 andWO 99/25853); Zn-finger targeted molecules (e.g., WO 01/52620; WO03/048345; and WO 00/42219); and other methods or combinations of theabove methods known to those of skill in the art.

Exemplary nucleotide sequences that may be altered by geneticengineering include, but are not limited to, those categorized below.

1. Transgenes that Confer Resistance to Insects or Disease and thatEncode:

(A) Plant disease resistance genes. Plant defenses are often activatedby specific interaction between the product of a disease resistance gene(R) in the plant and the product of a corresponding avirulence (Avr)gene in the pathogen. A plant variety can be transformed with clonedresistance gene to engineer plants that are resistant to specificpathogen strains. See, for example Jones et al., Science 266: 789 (1994)(cloning of the tomato Cf-9 gene for resistance to Cladosporium fulvum);Martin et al., Science 262: 1432 (1993) (tomato Pto gene for resistanceto Pseudomonas syringae pv. tomato encodes a protein kinase); Mindrinoset al., Cell 78: 1089 (1994) (Arabidopsis RSP2 gene for resistance toPseudomonas syringae), McDowell & Woffenden, (2003) Trends Biotechnol.21(4): 178-83 and Toyoda et al., (2002) Transgenic Res. 11(6):567-82. Aplant resistant to a disease is one that is more resistant to a pathogenas compared to the wild type plant.

(B) A Bacillus thuringiensis protein, a derivative thereof or asynthetic polypeptide modeled thereon. See, for example, Geiser et al.,Gene 48: 109 (1986), who disclose the cloning and nucleotide sequence ofa Bt delta-endotoxin gene. Moreover, DNA molecules encodingdelta-endotoxin genes can be purchased from American Type CultureCollection (Rockville, Md.), for example, under ATCC Accession Nos.40098, 67136, 31995 and 31998. Other non-limiting examples of Bacillusthuringiensis transgenes being genetically engineered are given in thefollowing patents and patent applications and hereby are incorporated byreference for this purpose: U.S. Pat. Nos. 5,188,960; 5,689,052;5,880,275; 5,986,177; 7,105,332; 7,208,474; WO 91/14778; WO 99/31248; WO01/12731; WO 99/24581; WO 97/40162 and U.S. application Ser. Nos.10/032,717; 10/414,637; 11/018,615; 11/404,297; 11/404,638; 11/471,878;11/780,501; 11/780,511; 11/780,503; 11/953,648; 11/953,648; and11/957,893.

(C) An insect-specific hormone or pheromone such as an ecdysteroid andjuvenile hormone, a variant thereof, a mimetic based thereon, or anantagonist or agonist thereof. See, for example, the disclosure byHammock et al., Nature 344: 458 (1990), of baculovirus expression ofcloned juvenile hormone esterase, an inactivator of juvenile hormone.

(D) An insect-specific peptide which, upon expression, disrupts thephysiology of the affected pest. For example, see the disclosures ofRegan, J. Biol. Chem. 269: 9 (1994) (expression cloning yields DNAcoding for insect diuretic hormone receptor); Pratt et al., Biochem.Biophys. Res. Comm. 163: 1243 (1989) (an allostatin is identified inDiploptera puntata); Chattopadhyay et al. (2004) Critical Reviews inMicrobiology 30 (1): 33-54 2004; Zjawiony (2004) J Nat Prod 67 (2):300-310; Carlini & Grossi-de-Sa (2002) Toxicon, 40 (11): 1515-1539;Ussuf et al. (2001) Curr Sci. 80 (7): 847-853; and Vasconcelos &Oliveira (2004) Toxicon 44 (4): 385-403. See also U.S. Pat. No.5,266,317 to Tomalski et al., who disclose genes encodinginsect-specific toxins.

(E) An enzyme responsible for a hyperaccumulation of a monterpene, asesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid derivativeor another non-protein molecule with insecticidal activity.

(F) An enzyme involved in the modification, including thepost-translational modification, of a biologically active molecule; forexample, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme,a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, aphosphatase, a kinase, a phosphorylase, a polymerase, an elastase, achitinase and a glucanase, whether natural or synthetic. See PCTapplication WO 93/02197 in the name of Scott et al., which discloses thenucleotide sequence of a callase gene. DNA molecules which containchitinase-encoding sequences can be obtained, for example, from the ATCCunder Accession Nos. 39637 and 67152. See also Kramer et al., InsectBiochem. Molec. Biol. 23: 691 (1993), who teach the nucleotide sequenceof a cDNA encoding tobacco hookworm chitinase, and Kawalleck et al.,Plant Molec. Biol. 21: 673 (1993), who provide the nucleotide sequenceof the parsley ubi4-2 polyubiquitin gene, and U.S. Pat. Nos. 6,563,020;7,145,060 and 7,087,810.

(G) A molecule that stimulates signal transduction. For example, see thedisclosure by Botella et al., Plant Molec. Biol. 24: 757 (1994), ofnucleotide sequences for mung bean calmodulin cDNA clones, and Griess etal., Plant Physiol. 104: 1467 (1994), who provide the nucleotidesequence of a maize calmodulin cDNA clone.

(H) A hydrophobic moment peptide. See PCT application WO 95/16776 andU.S. Pat. No. 5,580,852 disclosure of peptide derivatives of Tachyplesinwhich inhibit fungal plant pathogens) and PCT application WO 95/18855and U.S. Pat. No. 5,607,914 (teaches synthetic antimicrobial peptidesthat confer disease resistance).

(I) A membrane permease, a channel former or a channel blocker. Forexample, see the disclosure by Jaynes et al., Plant Sci. 89: 43 (1993),of heterologous expression of a cecropin-beta lytic peptide analog torender transgenic tobacco plants resistant to Pseudomonas solanacearum.

(J) A viral-invasive protein or a complex toxin derived therefrom. Forexample, the accumulation of viral coat proteins in transformed plantcells imparts resistance to viral infection and/or disease developmenteffected by the virus from which the coat protein gene is derived, aswell as by related viruses. See Beachy et al., Ann. Rev. Phytopathol.28: 451 (1990). Coat protein-mediated resistance has been conferred upontransformed plants against alfalfa mosaic virus, cucumber mosaic virus,tobacco streak virus, potato virus X, potato virus Y, tobacco etchvirus, tobacco rattle virus and tobacco mosaic virus. Id.

(K) An insect-specific antibody or an immunotoxin derived therefrom.Thus, an antibody targeted to a critical metabolic function in theinsect gut would inactivate an affected enzyme, killing the insect. Cf.Taylor et al., Abstract #497, SEVENTH INT'L SYMPOSIUM ON MOLECULARPLANT-MICROBE INTERACTIONS (Edinburgh, Scotland, 1994) (enzymaticinactivation in transgenic tobacco via production of single-chainantibody fragments).

(L) A virus-specific antibody. See, for example, Tavladoraki et al.,Nature 366: 469 (1993), who show that transgenic plants expressingrecombinant antibody genes are protected from virus attack.

(M) A developmental-arrestive protein produced in nature by a pathogenor a parasite. Thus, fungal endo alpha-1,4-D-polygalacturonasesfacilitate fungal colonization and plant nutrient release bysolubilizing plant cell wall homo-alpha-1,4-D-galacturonase. See Lamb etal., Bio/Technology 10: 1436 (1992). The cloning and characterization ofa gene which encodes a bean endopolygalacturonase-inhibiting protein isdescribed by Toubart et al., Plant J. 2: 367 (1992).

(N) A developmental-arrestive protein produced in nature by a plant. Forexample, Logemann et al., Bio/Technology 10: 305 (1992), have shown thattransgenic plants expressing the barley ribosome-inactivating gene havean increased resistance to fungal disease.

(O) Genes involved in the Systemic Acquired Resistance (SAR) Responseand/or the pathogenesis related genes. Briggs, S., Current Biology, 5(2)(1995), Pieterse & Van Loon (2004) Curr. Opin. Plant Bio. 7(4):456-64and Somssich (2003) Cell 113(7):815-6.

(P) Antifungal genes (Cornelissen and Melchers, Pl. Physiol.101:709-712, (1993) and Parijs et al., Planta 183:258-264, (1991) andBushnell et al., Can. J. of Plant Path. 20(2):137-149 (1998). Also seeU.S. application Ser. Nos. 09/950,933; 11/619,645; 11/657,710;11/748,994; 11/774,121 and U.S. Pat. Nos. 6,891,085 and 7,306,946.

(Q) Detoxification genes, such as for fumonisin, beauvericin,moniliformin and zearalenone and their structurally related derivatives.For example, see U.S. Pat. Nos. 5,716,820; 5,792,931; 5,798,255;5,846,812; 6,083,736; 6,538,177; 6,388,171 and 6,812,380.

(R) Cystatin and cysteine proteinase inhibitors. See U.S. Pat. No.7,205,453.

(S) Defensin genes. See WO03000863 and U.S. Pat. Nos. 6,911,577;6,855,865; 6,777,592 and 7,238,781.

(T) Genes conferring resistance to nematodes. See e.g. PCT ApplicationWO96/30517; PCT Application WO93/19181, WO 03/033651 and Urwin et al.,Planta 204:472-479 (1998), Williamson (1999) Curr Opin Plant Bio.2(4):327-31; and U.S. Pat. Nos. 6,284,948 and 7,301,069.

(U) Genes that confer resistance to Phytophthora Root Rot, such as theRps 1, Rps 1-a, Rps 1-b, Rps 1-c, Rps 1-d, Rps 1-e, Rps 1-k, Rps 2, Rps3-a, Rps 3-b, Rps 3-c, Rps 4, Rps 5, Rps 6, Rps 7 and other Rps genes.See, for example, Shoemaker et al, Phytophthora Root Rot Resistance GeneMapping in Soybean, Plant Genome IV Conference, San Diego, Calif.(1995).

(V) Genes that confer resistance to Brown Stem Rot, such as described inU.S. Pat. No. 5,689,035 and incorporated by reference for this purpose.

2. Transgenes that Confer Resistance to a Herbicide, for Example:

(A) A herbicide that inhibits the growing point or meristem, such as animidazolinone or a sulfonylurea. Exemplary genes in this category codefor mutant ALS and AHAS enzyme as described, for example, by Lee et al.,EMBO J. 7: 1241 (1988), and Miki et al., Theor. Appl. Genet. 80: 449(1990), respectively. See also, U.S. Pat. Nos. 5,605,011; 5,013,659;5,141,870; 5,767,361; 5,731,180; 5,304,732; 4,761,373; 5,331,107;5,928,937; and 5,378,824; U.S. application Ser. No. 11/683,737, andinternational publication WO 96/33270.

(B) Glyphosate (resistance imparted by mutant5-enolpyruvl-3-phosphikimate synthase (EPSP) and aroA genes,respectively) and other phosphono compounds such as glufosinate(phosphinothricin acetyl transferase (PAT) and Streptomyceshygroscopicus phosphinothricin acetyl transferase (bar) genes), andpyridinoxy or phenoxy proprionic acids and cyclohexones (ACCaseinhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835 toShah et al., which discloses the nucleotide sequence of a form of EPSPSwhich can confer glyphosate resistance. U.S. Pat. No. 5,627,061 to Barryet al. also describes genes encoding EPSPS enzymes. See also U.S. Pat.Nos. 6,566,587; 6,338,961; 6,248,876 B1; 6,040,497; 5,804,425;5,633,435; 5,145,783; 4,971,908; 5,312,910; 5,188,642; 4,940,835;5,866,775; 6,225,114 B1; 6,130,366; 5,310,667; 4,535,060; 4,769,061;5,633,448; 5,510,471; Re. 36,449; RE 37,287 E; and 5,491,288; andinternational publications EP1173580; WO 01/66704; EP1173581 andEP1173582, which are incorporated herein by reference for this purpose.Glyphosate resistance is also imparted to plants that express a genethat encodes a glyphosate oxido-reductase enzyme as described more fullyin U.S. Pat. Nos. 5,776,760 and 5,463,175, which are incorporated hereinby reference for this purpose. In addition glyphosate resistance can beimparted to plants by the over expression of genes encoding glyphosateN-acetyltransferase. See, for example, U.S. application Ser. Nos.10/427,692; 10/835,615 and 11/507,751. A DNA molecule encoding a mutantaroA gene can be obtained under ATCC accession No. 39256, and thenucleotide sequence of the mutant gene is disclosed in U.S. Pat. No.4,769,061 to Comai. European Patent Application No. 0 333 033 to Kumadaet al. and U.S. Pat. No. 4,975,374 to Goodman et al. disclose nucleotidesequences of glutamine synthetase genes which confer resistance toherbicides such as L-phosphinothricin. The nucleotide sequence of aphosphinothricin-acetyl-transferase gene is provided in European PatentNo. 0 242 246 and 0 242 236 to Leemans et al. De Greef et al.,Bio/Technology 7: 61 (1989), describe the production of transgenicplants that express chimeric bar genes coding for phosphinothricinacetyl transferase activity. See also, U.S. Pat. Nos. 5,969,213;5,489,520; 5,550,318; 5,874,265; 5,919,675; 5,561,236; 5,648,477;5,646,024; 6,177,616 B1; and 5,879,903, which are incorporated herein byreference for this purpose. Exemplary genes conferring resistance tophenoxy proprionic acids and cyclohexones, such as sethoxydim andhaloxyfop, are the Acc1-S1, Acc1-S2 and Acc1-S3 genes described byMarshall et al., Theor. Appl. Genet. 83: 435 (1992).

(C) A herbicide that inhibits photosynthesis, such as a triazine (psbAand gs+ genes) and a benzonitrile (nitrilase gene). Przibilla et al.,Plant Cell 3: 169 (1991), describe the transformation of Chlamydomonaswith plasmids encoding mutant psbA genes. Nucleotide sequences fornitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, andDNA molecules containing these genes are available under ATCC AccessionNos. 53435, 67441 and 67442. Cloning and expression of DNA coding for aglutathione S-transferase is described by Hayes et al., Biochem. J. 285:173 (1992).

(D) Acetohydroxy acid synthase, which has been found to make plants thatexpress this enzyme resistant to multiple types of herbicides, has beenintroduced into a variety of plants (see, e.g., Hattori et al. (1995)Mol Gen Genet. 246:419). Other genes that confer resistance toherbicides include: a gene encoding a chimeric protein of rat cytochromeP4507A1 and yeast NADPH-cytochrome P450 oxidoreductase (Shiota et al.(1994) Plant Physiol 106:17), genes for glutathione reductase andsuperoxide dismutase (Aono et al. (1995) Plant Cell Physiol 36:1687, andgenes for various phosphotransferases (Datta et al. (1992) Plant MolBiol 20:619).

(E) Protoporphyrinogen oxidase (protox) is necessary for the productionof chlorophyll, which is necessary for all plant survival. The protoxenzyme serves as the target for a variety of herbicidal compounds. Theseherbicides also inhibit growth of all the different species of plantspresent, causing their total destruction. The development of plantscontaining altered protox activity which are resistant to theseherbicides are described in U.S. Pat. Nos. 6,288,306 B1; 6,282,837 B1;and 5,767,373; and international publication WO 01/12825.

3. Transgenes that confer or contribute to an altered graincharacteristic, Such as:

(A) Altered fatty acids, for example, by

-   -   (1) Down-regulation of stearoyl-ACP desaturase to increase        stearic acid content of the plant. See Knultzon et al., Proc.        Natl. Acad. Sci. USA 89: 2624 (1992) and WO99/64579 (Genes for        Desaturases to Alter Lipid Profiles in Corn),    -   (2) Elevating oleic acid via FAD-2 gene modification and/or        decreasing linolenic acid via FAD-3 gene modification (see U.S.        Pat. Nos. 6,063,947; 6,323,392; 6,372,965 and WO 93/11245),    -   (3) Altering conjugated linolenic or linoleic acid content, such        as in WO 01/12800,    -   (4) Altering LEC1, AGP, Dek1, Superal1, mi1ps, various Ipa genes        such as Ipa1, Ipa3, hpt or hggt. For example, see WO 02/42424,        WO 98/22604, WO 03/011015, WO02/057439, WO03/011015, U.S. Pat.        Nos. 6,423,886, 6,197,561, 6,825,397, and U.S. Application        Serial Nos. US2003/0079247, US2003/0204870, and        Rivera-Madrid, R. et al. Proc. Natl. Acad. Sci. 92:5620-5624        (1995).

(B) Altered phosphorus content, for example, by the

-   -   (1) Introduction of a phytase-encoding gene would enhance        breakdown of phytate, adding more free phosphate to the        transformed plant. For example, see Van Hartingsveldt et al.,        Gene 127: 87 (1993), for a disclosure of the nucleotide sequence        of an Aspergillus niger phytase gene.    -   (2) Modulating a gene that reduces phytate content. In maize,        this, for example, could be accomplished, by cloning and then        re-introducing DNA associated with one or more of the alleles,        such as the LPA alleles, identified in maize mutants        characterized by low levels of phytic acid, such as in WO        05/113778 and/or by altering inositol kinase activity as in WO        02/059324, US2003/0009011, WO 03/027243, US2003/0079247, WO        99/05298, U.S. Pat. No. 6,197,561, U.S. Pat. No. 6,291,224, U.S.        Pat. No. 6,391,348, WO2002/059324, US2003/0079247, Wo98/45448,        WO99/55882, WO01/04147.

(C) Altered carbohydrates effected, for example, by altering a gene foran enzyme that affects the branching pattern of starch or, a genealtering thioredoxin such as NTR and/or TRX (see. (See U.S. Pat. No.6,531,648 which is incorporated by reference for this purpose) and/or agamma zein knock out or mutant such as cs27 or TUSC27 or en27 (See U.S.Pat. No. 6,858,778 and US2005/0160488, US2005/0204418; which areincorporated by reference for this purpose). See Shiroza et al., J.Bacteriol. 170: 810 (1988) (nucleotide sequence of Streptococcus mutansfructosyltransferase gene), Steinmetz et al., Mol. Gen. Genet. 200: 220(1985) (nucleotide sequence of Bacillus subtilis levansucrase gene), Penet al., Bio/Technology 10: 292 (1992) (production of transgenic plantsthat express Bacillus licheniformis alpha-amylase), Elliot et al., PlantMolec. Biol. 21: 515 (1993) (nucleotide sequences of tomato invertasegenes), Søgaard et al., J. Biol. Chem. 268: 22480 (1993) (site-directedmutagenesis of barley alpha-amylase gene), and Fisher et al., PlantPhysiol. 102: 1045 (1993) (maize endosperm starch branching enzyme II),WO 99/10498 (improved digestibility and/or starch extraction throughmodification of UDP-D-xylose 4-epimerase, Fragile 1 and 2, Ref1, HCHL,C4H), U.S. Pat. No. 6,232,529 (method of producing high oil seed bymodification of starch levels (AGP)). The fatty acid modification genesmentioned herein may also be used to affect starch content and/orcomposition through the interrelationship of the starch and oilpathways.

(D) Altered antioxidant content or composition, such as alteration oftocopherol or tocotrienols. For example, see U.S. Pat. No. 6,787,683,US2004/0034886 and WO 00/68393 involving the manipulation of antioxidantlevels, and WO 03/082899 through alteration of a homogentisate geranylgeranyl transferase (hggt).

(E) Altered essential seed amino acids. For example, see U.S. Pat. No.6,127,600 (method of increasing accumulation of essential amino acids inseeds), U.S. Pat. No. 6,080,913 (binary methods of increasingaccumulation of essential amino acids in seeds), U.S. Pat. No. 5,990,389(high lysine), WO99/40209 (alteration of amino acid compositions inseeds), WO99/29882 (methods for altering amino acid content ofproteins), U.S. Pat. No. 5,850,016 (alteration of amino acidcompositions in seeds), WO98/20133 (proteins with enhanced levels ofessential amino acids), U.S. Pat. No. 5,885,802 (high methionine), U.S.Pat. No. 5,885,801 (high threonine), U.S. Pat. No. 6,664,445 (plantamino acid biosynthetic enzymes), U.S. Pat. No. 6,459,019 (increasedlysine and threonine), U.S. Pat. No. 6,441,274 (plant tryptophansynthase beta subunit), U.S. Pat. No. 6,346,403 (methionine metabolicenzymes), U.S. Pat. No. 5,939,599 (high sulfur), U.S. Pat. No. 5,912,414(increased methionine), WO98/56935 (plant amino acid biosyntheticenzymes), WO98/45458 (engineered seed protein having higher percentageof essential amino acids), WO98/42831 (increased lysine), U.S. Pat. No.5,633,436 (increasing sulfur amino acid content), U.S. Pat. No.5,559,223 (synthetic storage proteins with defined structure containingprogrammable levels of essential amino acids for improvement of thenutritional value of plants), WO96/01905 (increased threonine),WO95/15392 (increased lysine), US2003/0163838, US2003/0150014,US2004/0068767, U.S. Pat. No. 6,803,498, WO01/79516.

4. Genes that Control Male-Sterility:

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Inaddition to these methods, Albertsen et al., U.S. Pat. No. 5,432,068,describe a system of nuclear male sterility which includes:

identifying a gene which is critical to male fertility; silencing thisnative gene which is critical to male fertility; removing the nativepromoter from the essential male fertility gene and replacing it with aninducible promoter; inserting this genetically engineered gene back intothe plant; and thus creating a plant that is male sterile because theinducible promoter is not “on” resulting in the male fertility gene notbeing transcribed. Fertility is restored by inducing, or turning “on”,the promoter, which in turn allows the gene that confers male fertilityto be transcribed.

(A) Introduction of a deacetylase gene under the control of atapetum-specific promoter and with the application of the chemicalN-Ac-PPT (WO 01/29237).

(B) Introduction of various stamen-specific promoters (WO 92/13956, WO92/13957).

(C) Introduction of the barnase and the barstar gene (Paul et al. PlantMol. Biol. 19:611-622, 1992).

For additional examples of nuclear male and female sterility systems andgenes, see also, U.S. Pat. Nos. 5,859,341; 6,297,426; 5,478,369;5,824,524; 5,850,014; and 6,265,640; all of which are herebyincorporated by reference.

5. Genes that create a site for site specific DNA integration. Thisincludes the introduction of FRT sites that may be used in the FLP/FRTsystem and/or Lox sites that may be used in the Cre/Loxp system. Forexample, see Lyznik, et al., Site-Specific Recombination for GeneticEngineering in Plants, Plant Cell Rep (2003) 21:925-932 and WO 99/25821which are hereby incorporated by reference. Other systems that may beused include the Gin recombinase of phage Mu (Maeser et al., 1991; VickiChandler, The Maize Handbook ch. 118 (Springer-Verlag 1994), the Pinrecombinase of E. coli (Enomoto et al., 1983), and the R/RS system ofthe pSRi plasmid (Araki et al., 1992).6. Genes that affect abiotic stress resistance (including but notlimited to flowering, ear and seed development, enhancement of nitrogenutilization efficiency, altered nitrogen responsiveness, droughtresistance or tolerance, cold resistance or tolerance, and saltresistance or tolerance) and increased yield under stress. For example,see: WO 00/73475 where water use efficiency is altered throughalteration of malate; U.S. Pat. Nos. 5,892,009, 5,965,705, 5,929,305,5,891,859, 6,417,428, 6,664,446, 6,706,866, 6,717,034, 6,801,104,WO2000060089, WO2001026459, WO2001035725, WO2001034726, WO2001035727,WO2001036444, WO2001036597, WO2001036598, WO2002015675, WO2002017430,WO2002077185, WO2002079403, WO2003013227, WO2003013228, WO2003014327,WO2004031349, WO2004076638, WO9809521, and WO9938977 describing genes,including CBF genes and transcription factors effective in mitigatingthe negative effects of freezing, high salinity, and drought on plants,as well as conferring other positive effects on plant phenotype;US2004/0148654 and WO01/36596 where abscisic acid is altered in plantsresulting in improved plant phenotype such as increased yield and/orincreased tolerance to abiotic stress; WO2000/006341, WO04/090143, U.S.application Ser. Nos. 10/817,483 and 09/545,334 where cytokininexpression is modified resulting in plants with increased stresstolerance, such as drought tolerance, and/or increased yield. Also seeWO0202776, WO2003052063, JP2002281975, U.S. Pat. No. 6,084,153,WO0164898, U.S. Pat. No. 6,177,275, and U.S. Pat. No. 6,107,547(enhancement of nitrogen utilization and altered nitrogenresponsiveness). For ethylene alteration, see US20040128719,US20030166197 and WO200032761. For plant transcription factors ortranscriptional regulators of abiotic stress, see e.g. US20040098764 orUS20040078852.

Other genes and transcription factors that affect plant growth andagronomic traits such as yield, flowering, plant growth and/or plantstructure, can be introduced or introgressed into plants, see e.g.WO97/49811 (LHY), WO98/56918 (ESD4), WO97/10339 and U.S. Pat. No.6,573,430 (TFL), U.S. Pat. No. 6,713,663 (FT), WO96/14414 (CON),WO96/38560, WO01/21822 (VRN1), WO00/44918 (VRN2), WO99/49064 (GI),WO00/46358 (FRI), WO97/29123, U.S. Pat. No. 6,794,560, U.S. Pat. No.6,307,126 (GAI), WO99/09174 (D8 and Rht), and WO2004076638 andWO2004031349 (transcription factors).

Using X6N745 to Develop Another Maize Plant

The development of maize hybrids in a maize plant breeding programrequires, in general, the development of homozygous inbred lines, thecrossing of these lines, and the evaluation of the crosses. Maize plantbreeding programs combine the genetic backgrounds from two or moreinbred varieties or various other germplasm sources into breedingpopulations from which new inbred varieties are developed by selfing andselection of desired phenotypes. Hybrids also can be used as a source ofplant breeding material or as source populations from which to developor derive new maize varieties. Plant breeding techniques known in theart and used in a maize plant breeding program include, but are notlimited to, recurrent selection, mass selection, bulk selection,backcrossing, making double haploids, pedigree breeding, openpollination breeding, restriction fragment length polymorphism enhancedselection, genetic marker enhanced selection, and transformation. Oftencombinations of these techniques are used. The inbred varieties derivedfrom hybrids can be developed using plant breeding techniques asdescribed above. New inbreds are crossed with other inbred varieties andthe hybrids from these crosses are evaluated to determine which of thosehave commercial potential. The oldest and most traditional method ofanalysis is the observation of phenotypic traits but genotypic analysismay also be used. Descriptions of breeding methods can also be found inone of several reference books (e.g., Allard, Principles of PlantBreeding, 1960; Simmonds, Principles of Crop Improvement, 1979; Fehr,“Breeding Methods for Cultivar Development”, Production and Uses, 2^(nd)ed., Wilcox editor, 1987).

Recurrent Selection and Mass Selection

Recurrent selection is a method used in a plant breeding program toimprove a population of plants. X6N745 is suitable for use in arecurrent selection program. The method entails individual plants crosspollinating with each other to form progeny. The progeny are grown andthe superior progeny selected by any number of selection methods, whichinclude individual plant, half-sib progeny, full-sib progeny, selfedprogeny and toperossing. The selected progeny are cross pollinated witheach other to form progeny for another population. This population isplanted and again superior plants are selected to cross pollinate witheach other. Recurrent selection is a cyclical process and therefore canbe repeated as many times as desired. The objective of recurrentselection is to improve the traits of a population. The improvedpopulation can then be used as a source of breeding material to obtaininbred varieties to be used in hybrids or used as parents for asynthetic cultivar. A synthetic cultivar is the resultant progeny formedby the intercrossing of several selected inbreds.

X6N745 is suitable for use in mass selection. Mass selection is a usefultechnique when used in conjunction with molecular marker enhancedselection. In mass selection seeds from individuals are selected basedon phenotype and/or genotype. These selected seeds are then bulked andused to grow the next generation. Bulk selection requires growing apopulation of plants in a bulk plot, allowing the plants toself-pollinate, harvesting the seed in bulk and then using a sample ofthe seed harvested in bulk to plant the next generation. Instead of selfpollination, directed pollination could be used as part of the breedingprogram.

Mutation Breeding

Mutation breeding is one of many methods that could be used to introducenew traits into X6N745 by mutating one or more of the parental maizeinbred varieties of X6N745. X6N745 is suitable for use in a mutationbreeding program. Mutations that occur spontaneously or are artificiallyinduced can be useful sources of variability for a plant breeder. Thegoal of artificial mutagenesis is to increase the rate of mutation for adesired characteristic. Mutation rates can be increased by manydifferent means including temperature, long-term seed storage, tissueculture conditions, radiation; such as X-rays, Gamma rays (e.g. cobalt60 or cesium 137), neutrons, (product of nuclear fission by uranium 235in an atomic reactor), Beta radiation (emitted from radioisotopes suchas phosphorus 32 or carbon 14), or ultraviolet radiation (preferablyfrom 2500 to 2900 nm), or chemical mutagens (such as base analogues(5-bromo-uracil), related compounds (8-ethoxy caffeine), antibiotics(streptonigrin), alkylating agents (sulfur mustards, nitrogen mustards,epoxides, ethylenamines, sulfates, sulfonates, sulfones, lactones),azide, hydroxylamine, nitrous acid, or acridines. Once a desired traitis observed through mutagenesis the trait may then be incorporated intoexisting germplasm by traditional breeding techniques, such asbackcrossing. Details of mutation breeding can be found in “Principlesof Cultivar Development” Fehr, 1993 Macmillan Publishing Company, thedisclosure of which is incorporated herein by reference. In addition,mutations created in other varieties may be used to produce a backcrossconversion of X6N745 that comprises such mutation.

Breeding with Molecular Markers

Molecular markers, which includes markers identified through the use oftechniques such as Isozyme Electrophoresis, Restriction Fragment LengthPolymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs),Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA AmplificationFingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs),Amplified Fragment Length Polymorphisms (AFLPs), Single NucleotidePolymorphisms (SNPs) and Simple Sequence Repeats (SSRs) may be used onX6N745.

Isozyme Electrophoresis and RFLPs as discussed in Lee, M., “Inbred Linesof Maize and Their Molecular Markers,” The Maize Handbook,(Springer-Verlag, New York, Inc. 1994, at 423-432) incorporated hereinby reference, have been widely used to determine genetic composition.Isozyme Electrophoresis has a relatively low number of available markersand a low number of allelic variants. RFLPs allow more discriminationbecause they have a higher degree of allelic variation in maize and alarger number of markers can be found. Both of these methods have beeneclipsed by SSRs as discussed in Smith et al., “An evaluation of theutility of SSR loci as molecular markers in maize (Zea mays L.):comparisons with data from RFLPs and pedigree”, Theoretical and AppliedGenetics (1997) vol. 95 at 163-173 and by Pejic et al., “Comparativeanalysis of genetic similarity among maize inbreds detected by RFLPs,RAPDs, SSRs, and AFLPs,” Theoretical and Applied Genetics (1998) at1248-1255 incorporated herein by reference. SSR technology is moreefficient and practical to use than RFLPs; more marker loci can beroutinely used and more alleles per marker locus can be found using SSRsin comparison to RFLPs. Single Nucleotide Polymorphisms may also be usedto identify the unique genetic composition of the invention and progenyvarieties retaining that unique genetic composition. Various molecularmarker techniques may be used in combination to enhance overallresolution.

Maize DNA molecular marker linkage maps have been rapidly constructedand widely implemented in genetic studies. One such study is describedin Boppenmaier, et al., “Comparisons among strains of inbreds forRFLPs”, Maize Genetics Cooperative Newsletter, 65:1991, pg. 90, isincorporated herein by reference.

A genetic marker profile of a hybrid should be the sum of its inbredparents, e.g., if one inbred parent is homozygous for allele x at aparticular locus, and the other inbred parent is homozygous for allele yat that locus, the F1 hybrid will be x.y (heterozygous) at that locus.The profile can therefore be used to identify the inbred parents ofmaize variety X6N745. The determination of the male set of alleles andthe female set of alleles may be made by profiling the hybrid and thepericarp of the hybrid seed, which is composed of maternal parent cells.The paternal parent profile is obtained by subtracting the pericarpprofile from the hybrid profile.

Molecular markers can also be used to reduce the number of crosses backto the recurrent parent needed in a backcrossing program. Withbackcrossing, the expected contribution of a parental maize inbredvariety of maize variety X6N745 after 2, 3, 4 and 5 doses (or 1, 2, 3and 4 backcrosses) would be 75%, 87.5%, 93.75% and 96.875% respectively.Actual genetic contribution may be much higher than the geneticcontribution expected by pedigree, especially if molecular markers areused in selection. The use of molecular markers in the selection processis often called genetic marker enhanced selection.

Production of Double Haploids

The production of double haploids can also be used for the developmentof inbreds. Double haploids are produced by the doubling of a set ofchromosomes (1N) from a heterozygous plant to produce a completelyhomozygous individual. For example, a further embodiment of thisinvention is the method of obtaining a substantially homozygous X6N745progeny plant by obtaining a seed from the cross of X6N745 and anothermaize plant and applying double haploid methods to the F1 seed or F1plant or to any successive filial generation. Such methods substantiallydecrease the number of generations required to produce an inbred withsimilar genetics or characteristics to X6N745. For example, see Wan etal., “Efficient Production of Doubled Haploid Plants Through ColchicineTreatment of Anther-Derived Maize Callus”, Theoretical and AppliedGenetics, 77:889-892, 1989 and U.S. Patent Application 2003/0005479.This can be advantageous because the process omits the generations ofselfing needed to obtain a homozygous plant from a heterozygous source.

Haploid induction systems have been developed for various plants toproduce haploid tissues, plants and seeds. The haploid induction systemcan produce haploid plants from any genotype by crossing a selectedvariety (as female) with an inducer variety. Such inducer varieties formaize include Stock 6 (Coe, 1959, Am. Nat. 93:381-382; Sharkar and Coe,1966, Genetics 54:453-464) RWS (see the World Wide Web atuni-hohenheim.de/%7Eipspwww/350b/indexe.html#Project3), KEMS (Deimling,Roeber, and Geiger, 1997, Vortr. Pflanzenzuchtg 38:203-224), or KMS andZMS (Chalyk, Bylich & Chebotar, 1994, MNL 68:47; Chalyk & Chebotar,2000, Plant Breeding 119:363-364), and indeterminate gametophyte (ig)mutation (Kermicle 1969 Science 166:1422-1424), the disclosures of whichare incorporated herein by reference.

Methods for obtaining haploid plants are also disclosed in Kobayashi, M.et al., Journ. of Heredity 71(1):9-14, 1980, Pollacsek, M., Agronomie(Paris) 12(3):247-251, 1992; Cho-Un-Haing et al., Journ. of Plant Biol.,1996, 39(3):185-188; Verdoodt, L., et al., February 1998, 96(2):294-300;Genetic Manipulation in Plant Breeding, Proceedings InternationalSymposium Organized by EUCARPIA, Sep. 8-13, 1985, Berlin, Germany;Chalyk et al., 1994, Maize Genet Coop. Newsletter 68:47; Chalyk, S. T.,1999, Maize Genet. Coop. Newsletter 73:53-54; Coe, R. H., 1959, Am. Nat.93:381-382; Deimling, S. et al., 1997, Vortr. Pflanzenzuchtg 38:203-204;Kato, A., 1999, J. Hered. 90:276-280; Lashermes, P. et al., 1988, Theor.Appl. Genet. 76:570-572 and 76:405-410; Tyrnov, V. S. et al., 1984,Dokl. Akad. Nauk. SSSR 276:735-738; Zabirova, E. R. et al., 1996,Kukuruza I Sorgo N4, 17-19; Aman, M. A., 1978, Indian J. Genet PlantBreed 38:452-457; Chalyk S. T., 1994, Euphytica 79:13-18; Chase, S. S.,1952, Agron. J. 44:263-267; Coe, E. H., 1959, Am. Nat. 93:381-382; Coe,E. H., and Sarkar, K. R., 1964 J. Hered. 55:231-233; Greenblatt, I. M.and Bock, M., 1967, J. Hered. 58:9-13; Kato, A., 1990, Maize Genet.Coop. Newsletter 65:109-110; Kato, A., 1997, Sex. Plant Reprod.10:96-100; Nanda, D. K. and Chase, S. S., 1966, Crop Sci. 6:213-215;Sarkar, K. R. and Coe, E. H., 1966, Genetics 54:453-464; Sarkar, K. R.and Coe, E. H., 1971, Crop Sci. 11:543-544; Sarkar, K. R. and Sachan J.K. S., 1972, Indian J. Agric. Sci. 42:781-786; Kermicle J. L., 1969,Mehta Yeshwant, M. R., Genetics and Molecular Biology, September 2000,23(3):617-622; Tahir, M. S. et al. Pakistan Journal of Scientific andIndustrial Research, August 2000, 43(4):258-261; Knox, R. E. et al.Plant Breeding, August 2000, 119(4):289-298; U.S. Pat. No. 5,639,951 andU.S. patent application Ser. No. 10/121,200, the disclosures of whichare incorporated herein by reference.

Use of X6N745 in Tissue Culture

This invention is also directed to the use of maize variety X6N745 intissue culture. As used herein, the term “tissue culture” includes plantprotoplasts, plant cell tissue culture, cultured microspores, plantcalli, plant clumps, and the like. As used herein, phrases such as“growing the seed” or “grown from the seed” include embryo rescue,isolation of cells from seed for use in tissue culture, as well astraditional growing methods.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflectsthat 97% of the plants cultured which produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus which produced plants. In a furtherstudy in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions which enhance regenerabilityof callus of two inbred varieties. Other published reports alsoindicated that “nontraditional” tissues are capable of producing somaticembryogenesis and plant regeneration. K. P. Rao, et al., Maize GeneticsCooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesisfrom glume callus cultures and B. V. Conger, et al., Plant Cell Reports,6:345-347 (1987) indicates somatic embryogenesis from the tissuecultures of maize leaf segments. Thus, it is clear from the literaturethat the state of the art is such that these methods of obtaining plantsare, and were, “conventional” in the sense that they are routinely usedand have a very high rate of success.

Tissue culture of maize, including tassel/anther culture, is describedin U.S. Application 2002/0062506A1 and European Patent Application,Publication EP0160,390, each of which are incorporated herein byreference for this purpose. Maize tissue culture procedures are alsodescribed in Green and Rhodes, “Plant Regeneration in Tissue Culture ofMaize,” Maize for Biological Research (Plant Molecular BiologyAssociation, Charlottesville, Virginia 1982, at 367-372) and in Duncan,et al., “The Production of Callus Capable of Plant Regeneration fromImmature Embryos of Numerous Zea Mays Genotypes,” 165 Planta 322-332(1985). Thus, another aspect of this invention is to provide cells whichupon growth and differentiation produce maize plants having the genotypeand/or morphological and physiological characteristics of maize varietyX6N745.

This invention includes maize seed of X6N745 and the maize plantproduced therefrom. The foregoing was set forth by way of example and isnot intended to limit the scope of the invention.

INDUSTRIAL APPLICABILITY

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.The principal products of maize dry milling are grits, meal and flour.The maize wet-milling industry can provide maize starch, maize syrups,and dextrose for food use. Maize oil is recovered from maize germ, whichis a by-product of both dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry: forexample, stalks and husks are made into paper and wallboard and cobs areused for fuel and to make charcoal.

The seed of the maize variety, the plant produced from the seed, a plantproduced from crossing of maize variety X6N745 and various parts of themaize plant and transgenic versions of the foregoing, can be utilizedfor human food, livestock feed, and as a raw material in industry.

REFERENCES

-   Aukerman, M. J. et al. (2003) “Regulation of Flowering Time and    Floral Organ Identity by a MicroRNA and Its APETALA2-like Target    Genes” The Plant Cell 15:2730-2741-   Berry et al., “Assessing Probability of Ancestry Using Simple    Sequence Repeat Profiles: Applications to Maize Hybrids and    Inbreds”, Genetics 161:813-824 (2002)-   Berry et al., “Assessing Probability of Ancestry Using Simple    Sequence Repeat Profiles: Applications to Maize Inbred Lines and    Soybean Varieties” Genetics 165:331-342 (2003)-   Boppenmaier, et al., “Comparisons Among Strains of Inbreds for    RFLPs”, Maize Genetics Cooperative Newsletter, 65:1991, p. 90-   Conger, B. V., et al. (1987) “Somatic Embryogenesis From Cultured    Leaf Segments of Zea Mays”, Plant Cell Reports, 6:345-347-   Duncan, D. R., et al. (1985) “The Production of Callus Capable of    Plant Regeneration From Immature Embryos of Numerous Zea Mays    Genotypes”, Planta, 165:322-332-   Edallo, et al. (1981) “Chromosomal Variation and Frequency of    Spontaneous Mutation Associated with in Vitro Culture and Plant    Regeneration in Maize”, Maydica, XXVI: 39-56-   Fehr, Walt, Principles of Cultivar Development, pages 261-286 (1987)-   Green, et al. (1975) “Plant Regeneration From Tissue Cultures of    Maize”, Crop Science, Vol. 15, pages 417-421-   Green, C. E., et al. (1982) “Plant Regeneration in Tissue Cultures    of Maize” Maize for Biological Research, pages 367-372-   Hallauer, A. R. et al. (1988) “Corn Breeding” Corn and Corn    Improvement, No. 18, pages 463-481-   Lee, Michael (1994) “Inbred Lines of Maize and Their Molecular    Markers”, The Maize Handbook, Ch. 65:423-432-   Meghji, M. R., et al. (1984) “Inbreeding Depression, Inbred & Hybrid    Grain Yields, and Other Traits of Maize Genotypes Representing Three    Eras”, Crop Science, Vol. 24, pages 545-549-   Openshaw, S. J., et al. (1994) “Marker-assisted selection in    backcross breeding”, pages 41-43. In Proceedings of the Symposium    Analysis of Molecular Marker Data. 5-7 Aug. 1994. Corvallis, Oreg.,    American Society for Horticultural Science/Crop Science Society of    America-   Phillips, et al. (1988) “Cell/Tissue Culture and In Vitro    Manipulation”, Corn & Corn Improvement, 3rd Ed., ASA Publication,    No. 18, pages 345-387-   Poehlman et al. (1995) Breeding Field Crop, 4th Ed., Iowa State    University Press, Ames, I A., pages 132-155 and 321-344-   Rao, K. V., et al., (1986) “Somatic Embryogenesis in Glume Callus    Cultures”, Maize Genetics Cooperative Newsletter, No. 60, pages    64-65-   Sass, John F. (1977) “Morphology”, Corn & Corn Improvement, ASA    Publication, Madison, Wis. pages 89-109-   Smith, J. S. C., et al., “The Identification of Female Selfs in    Hybrid Maize: A Comparison Using Electrophoresis and Morphology”,    Seed Science and Technology 14, 1-8-   Songstad, D. D. et al. (1988) “Effect of    ACC(1-aminocyclopropane-1-carboyclic acid), Silver Nitrate &    Norbonadiene on Plant Regeneration From Maize Callus Cultures”,    Plant Cell Reports, 7:262-265-   Tomes, et al. (1985) “The Effect of Parental Genotype on Initiation    of Embryogenic Callus From Elite Maize (Zea Mays L.) Germplasm”,    Theor. Appl. Genet., Vol. 70, p. 505-509-   Troyer, et al. (1985) “Selection for Early Flowering in Corn: 10    Late Synthetics”, Crop Science, Vol. 25, pages 695-697-   Umbeck, et al. (1983) “Reversion of Male-Sterile T-Cytoplasm Maize    to Male Fertility in Tissue Culture”, Crop Science, Vol. 23, pages    584-588-   Wan et al., “Efficient Production of Doubled Haploid Plants Through    Colchicine Treatment of Anther-Derived Maize Callus”, Theoretical    and Applied Genetics, 77:889-892, 1989-   Wright, Harold (1980) “Commercial Hybrid Seed Production”,    Hybridization of Crop Plants, Ch. 8:161-176-   Wych, Robert D. (1988) “Production of Hybrid Seed”, Corn and Corn    Improvement, Ch. 9, pages 565-607    Deposits

Applicant(s) have made a deposit of at least 2500 seeds of parentalmaize inbred varieties GE5339608 and GE68785637 with the American TypeCulture Collection (ATCC), Manassas, Va. 20110 USA, ATCC Deposit Nos.PTA-11577 and PTA-11582, respectively. The seeds deposited with the ATCCon Dec. 22, 2010, were taken from the deposit maintained by PioneerHi-Bred International, Inc., 7250 NW 62^(nd) Avenue, Johnston, Iowa50131-1000 since prior to the filing date of this application. Access tothis deposit will be available during the pendency of the application tothe Commissioner of Patents and Trademarks and persons determined by theCommissioner to be entitled thereto upon request. Upon allowance of anyclaims in the application, the Applicant(s) will make available to thepublic, pursuant to 37 C.F.R. §1.808, sample(s) of the deposit of atleast 2500 seeds of parental maize inbred varieties GE5339608 andGE68785637 with the American Type Culture Collection (ATCC), UniversityBoulevard, Manassas, Va. 20110-2209. This deposit of seed of parentalmaize inbred varieties GE5339608 and GE68785637 will be maintained inthe ATCC depository, which is a public depository, for a period of 30years, or 5 years after the most recent request, or for the enforceablelife of the patent, whichever is longer, and will be replaced if itbecomes nonviable during that period. Additionally, Applicant(s) havesatisfied all the requirements of 37 C.F.R. §§1.801-1.809, includingproviding an indication of the viability of the sample upon deposit.Applicant(s) have no authority to waive any restrictions imposed by lawon the transfer of biological material or its transportation incommerce. Applicant(s) do not waive any infringement of their rightsgranted under this patent or rights applicable to Maize Variety X6N745and parental maize inbred varieties GE5339608 and GE68785637 under thePlant Variety Protection Act (7 USC 2321 et seq.). U.S. Plant VarietyProtection of parental maize inbred varieties GE5339608 and GE68785637has been applied for. Unauthorized seed multiplication prohibited.

TABLE 1 VARIETY DESCRIPTION INFORMATION X6N745 1. TYPE: (Describeintermediate types in comments section) AVG STDEV N 1 = Sweet, 2 = Dent,3 = Flint, 4 = Flour, 5 = Pop and 3 6 = Ornamental. Comments: Flint-Dent2. MATURITY: DAYS HEAT UNITS Days H.Units Emergence to 50% of plants insilk 54 1,144 Emergence to 50% of plants in pollen shed 54 1,144 10% to90% pollen shed 2 54 50% Silk to harvest at 25% moisture 3. PLANT: PlantHeight (to tassel tip) (cm) 271.6 16.50 10 Ear Height (to base of topear node) (cm) 115.4 7.12 10 Length of Top Ear Internode (cm) 17.4 4.1410 Average Number of Tillers per Plant 0.1 0.07 2 Average Number of Earsper Stalk 1.0 0.03 2 Anthocyanin of Brace Roots: 1 = Absent, 2 = Faint,2 3 = Moderate, 4 = Dark 4. LEAF: Width of Ear Node Leaf (cm) 9.2 0.4210 Length of Ear Node Leaf (cm) 93.8 3.88 10 Number of Leaves above TopEar 6.6 0.52 10 Leaf Angle: (at anthesis, 2nd leaf above ear to 25.55.13 10 stalk above leaf) (Degrees) * Leaf Color: V. Dark Green Munsell:5GY36 Leaf Sheath Pubescence: 1 = none to 9 = like peach fuzz 3 5.TASSEL: Number of Primary Lateral Branches 4.7 1.06 10 Branch Angle fromCentral Spike 21.1 4.18 10 Tassel Length: (from peduncle node to tasseltip), (cm). 65.1 3.28 10 Pollen Shed: 0 = male sterile, 9 = heavy shed6 * Anther Color: (Pink) Salmon Munsell: 2.5YR66 * Glume Color: RedMunsell: 2.5R38 Bar Glumes (glume bands): 1 = absent, 2 = present 1Peduncle Length: (from top leaf node to lower florets or 25.7 3.71 10branches), (cm). 6a. EAR (Unhusked ear) * Silk color: Light GreenMunsell: 2.5GY88 (3 days after silk emergence) * Fresh husk color: Med.Green Munsell: 5GY78 * Dry husk color: Buff Munsell: 2.5Y84 (65 daysafter 50% silking) Ear position at dry husk stage: 1 = upright, 2 =horizontal, 2 3 = pendant Husk Tightness: (1 = very loose, 9 = verytight) 7 Husk Extension (at harvest): 1 = short(ears exposed), 2 2 =medium (<8 cm), 3 = long (8-10 cm), 4 = v. long (>10 cm) 6b. EAR (Huskedear data) Ear Length (cm): 18.4 0.84 10 Ear Diameter at mid-point (mm)46.8 1.23 10 Ear Weight (gm): 186.5 20.15 10 Number of Kernel Rows: 15.81.14 10 Kernel Rows: 1 = indistinct, 2 = distinct 2 Row Alignment: 1 =straight, 2 = slightly curved, 3 = spiral 1 Shank Length (cm): 11.0 1.4110 Ear Taper: 1 = slight cylind., 2 = average, 3 = extreme conic. 3 7.KERNEL (Dried): Kernel Length (mm): 12.8 0.42 10 Kernel Width (mm): 8.30.48 10 Kernel Thickness (mm): 4.9 0.32 10 Round Kernels (shape grade)(%) 28.7 2.90 2 Aleurone Color Pattern: 1 = homozygous, 2 = segregating1 * Aleurone Color: Yellow Munsell: 10YR814 * Hard Endo. Color: YellowMunsell: 10YR714 Endosperm Type: 3 1 = sweet (su1), 2 = extra sweet(sh2), 3 = normal starch, 4 = high amylose starch, 5 = waxy starch, 6 =high protein, 7 = high lysine, 8 = super sweet (se), 9 = high oil, 10 =other Weight per 100 Kernels (unsized sample) (gm): 35.0 0.00 2 8. COB:Cob Diameter at mid-point (mm): 23.9 0.57 10 * Cob Color: Red Munsell:10R38 9. DISEASE RESISTANCE: (Rate from 1 = most-susceptable to 9 =most-resistant. Leave blank if not tested, leave race or strain optionsblank if polygenic.) A. LEAF BLIGHTS, WILTS, AND LOCAL INFECTIONDISEASES Anthracnose Leaf Blight (Colletotrichum graminicola) CommonRust (Puccinia sorghi) 9 Common Smut (Ustilago maydis) Eyespot(Kabatiella zeae) 8 Goss's Wilt (Clavibacter michiganense spp.nebraskense) 5 Gray Leaf Spot (Cercospora zeae-maydis) HelminthosporiumLeaf Spot (Bipolaris zeicola) Race: 6 Northern Leaf Blight (Exserohilumturcicum) Race: Southern Leaf Blight (Bipolaris maydis) Race: SouthernRust (Puccinia polysora) 6 Stewart's Wilt (Erwinia stewartii) Other(Specify): ____________ B. SYSTEMIC DISEASES Corn Lethal Necrosis (MCMVand MDMV) 8 Head Smut (Sphacelotheca reiliana) Maize Chlorotic DwarfVirus (MDV) Maize Chlorotic Mottle Virus (MCMV) Maize Dwarf Mosaic Virus(MDMV) Sorghum Downy Mildew of Corn (Peronosclerospora sorghi) Other(Specify): ____________ C. STALK ROTS 4 Anthracnose Stalk Rot(Colletotrichum graminicola) Diplodia Stalk Rot (Stenocarpella maydis)Fusarium Stalk Rot (Fusarium moniliforme) Gibberella Stalk Rot(Gibberella zeae) Other (Specify): ____________ D. EAR AND KERNEL ROTSAspergillus Ear and Kernel Rot (Aspergillus flavus) 6 Diplodia Ear Rot(Stenocarpella maydis) 4 Fusarium Ear and Kernel Rot (Fusariummoniliforme) 7 Gibberella Ear Rot (Gibberella zeae) Other (Specify):____________ 10. INSECT RESISTANCE: (Rate from 1 = most-suscept. to 9 =most-resist., leave blank if not tested.) Corn Worm (Helicoverpa zea)___Leaf Feeding ___Silk Feeding ___Ear Damage Corn Leaf Aphid(Rophalosiphum maydis) Corn Sap Beetle (Capophilus dimidiatus) EuropeanCorn Borer (Ostrinia nubilalis) 8 1st. Generation (Typically whorl leaffeeding) 4 2nd. Generation (Typically leaf sheath-collar feeding)___Stalk Tunneling ___cm tunneled/plant Fall armyworm (Spodopterafruqiperda) ___Leaf Feeding ___Silk Feeding ___mg larval wt. MaizeWeevil (Sitophilus zeamaize) Northern Rootworm (Diabrotica barberi)Southern Rootworm (Diabrotica undecimpunctata) Southwestern Corn Borer(Diatreaea grandiosella) ___Leaf Feeding ___Stalk Tunneling ___cmtunneled/plant Two-spotted Spider Mite (Tetranychus utricae) WesternRootworm (Diabrotica virgifrea virgifrea) Other (Specify):____________11. AGRONOMIC TRAITS: 5 Staygreen (at 65 days after anthesis; rate from1-worst to 9-excellent) 0 % Dropped Ears (at 65 days after anthesis) %Pre-anthesis Brittle Snapping 10 % Pre-anthesis Root Lodging 8 %Post-anthesis Root Lodging (at 65 days after anthesis) 12 %Post-anthesis Stalk Lodging 11,716.0 Kg/ha (Yield at 12-13% grainmoisture) * Munsell Glossy Book of Color, (A standard color reference).Kollmorgen Inst. Corp. New Windsor, NY.

TABLE 2A HYBRID COMPARISON Variety #1: X6N745 Variety #2: 36W66 YIELDGLFSPT YIELD NLFBLT MST BU/A 56# SCORE BU/A 56# SCORE PCT Stat ABS ABS %MN ABS ABS Mean1 186.3 4.5 98.3 6.4 20.2 Mean2 189.1 5.3 99.9 6.2 21.8Locs 161 3 161 5 164 Reps 213 5 213 9 217 Diff −2.7 −0.8 −1.6 0.2 1.6Prob 0.042 0.300 0.042 0.772 0.000 TSTWT STWWLT ANTROT GIBERS STKCNTLB/BU SCORE SCORE SCORE COUNT Stat ABS ABS ABS ABS ABS Mean1 55.4 6.33.5 7.1 57.6 Mean2 54.5 4.3 8.5 5.5 57.9 Locs 85 2 1 6 201 Reps 107 4 26 295 Diff 0.8 2.0 −5.0 1.6 −0.3 Prob 0.000 0.156 . 0.036 0.033 DIPERSGDUSHD GDUSLK PLTHT EARHT SCORE GDU GDU CM CM Stat ABS ABS ABS ABS ABSMean1 6.0 123.9 122.8 283.5 124.2 Mean2 3.5 124.3 124.8 281.2 119.6 Locs1 26 24 47 47 Reps 2 41 31 67 67 Diff 2.5 −0.4 −2.0 2.3 4.6 Prob . 0.3890.000 0.197 0.003 STAGRN GIBROT HDSMT STLLPN STLPCN SCORE SCORE % NOT %NOT % NOT Stat ABS ABS ABS ABS ABS Mean1 5.5 4.7 87.3 70.8 88.5 Mean26.0 6.4 99.1 86.1 92.2 Locs 31 3 4 12 12 Reps 43 6 8 20 23 Diff −0.5−1.8 −11.9 −15.3 −3.7 Prob 0.051 0.206 0.421 0.019 0.104 ERTLPN ECBLSILRTLPN BRLPNE HSKCVR % NOT SCORE % NOT PCTNOT SCORE Stat ABS ABS ABS ABSABS Mean1 87.9 8.0 92.5 97.2 6.5 Mean2 94.9 6.0 93.7 91.7 6.3 Locs 8 120 1 13 Reps 9 1 29 6 18 Diff −7.0 2.0 −1.2 0.0 0.2 Prob 0.315 . 0.650 .0.700

TABLE 2B HYBRID COMPARISON Variety #1: X6N745 Variety #2: 37F73 YIELDGLFSPT YIELD NLFBLT MST BU/A 56# SCORE BU/A 56# SCORE PCT Stat ABS ABS %MN ABS ABS Mean1 189.3 4.9 99.3 6.3 20.6 Mean2 187.6 5.0 98.5 6.0 20.6Locs 142 4 142 6 145 Reps 219 6 219 12 223 Diff 1.6 −0.1 0.9 0.3 0.0Prob 0.214 0.391 0.258 0.640 0.634 TSTWT STWWLT ANTROT GIBERS STKCNTLB/BU SCORE SCORE SCORE COUNT Stat ABS ABS ABS ABS ABS Mean1 55.3 6.33.5 6.7 56.6 Mean2 55.4 5.4 5.0 6.4 56.0 Locs 78 2 1 5 189 Reps 115 4 26 307 Diff −0.2 0.9 −1.5 0.3 0.6 Prob 0.167 0.090 . 0.398 0.003 DIPERSGDUSHD GDUSLK PLTHT EARHT SCORE GDU GDU CM CM Stat ABS ABS ABS ABS ABSMean1 6.0 124.2 122.8 286.0 125.5 Mean2 4.3 124.3 124.1 288.4 125.6 Locs1 25 22 44 44 Reps 2 47 32 75 75 Diff 1.8 −0.1 −1.3 −2.3 -0.1 Prob .0.775 0.027 0.164 0.934 STAGRN GIBROT HDSMT STLLPN STLPCN SCORE SCORE %NOT % NOT % NOT Stat ABS ABS ABS ABS ABS Mean1 5.5 4.7 87.3 69.5 91.2Mean2 5.9 3.9 98.4 81.0 93.6 Locs 28 3 4 14 10 Reps 50 6 8 22 25 Diff−0.4 0.8 −11.1 −11.5 −2.4 Prob 0.086 0.591 0.427 0.042 0.409 ERTLPNECBLSI LRTLPN BRLPNE HSKCVR % NOT SCORE % NOT PCTNOT SCORE Stat ABS ABSABS ABS ABS Mean1 89.2 8.0 92.9 97.2 6.4 Mean2 84.2 8.0 89.0 88.3 5.0Locs 9 1 17 1 11 Reps 13 1 30 6 16 Diff 5.0 0.0 3.9 0.0 1.4 Prob 0.298 .0.455 . 0.032

TABLE 2C HYBRID COMPARISON Variety #1: X6N745 Variety #2: 37V63 YIELDYIELD NLFBLT MST TSTWT GIBERS STKCNT GDUSHD GDUSLK BU/A 56# BU/A 56#SCORE PCT LB/BU SCORE COUNT GDU GDU Stat ABS % MN ABS ABS ABS ABS ABSABS ABS Mean1 174.9 94.9 7.0 18.5 55.7 9.0 62.6 121.1 121.6 Mean2 187.4102.6 4.0 18.1 56.3 9.0 63.3 120.9 122.4 Locs 52 52 1 53 17 1 55 7 7Reps 57 57 1 58 18 1 60 7 7 Diff −12.5 −7.7 3.0 −0.4 −0.6 0.0 −0.7 0.3−0.9 Prob 0.000 0.000 . 0.025 0.204 . 0.012 0.703 0.111 PLTHT EARHTSTAGRN STLLPN STLPCN ERTLPN LRTLPN HSKCVR CM CM SCORE % NOT % NOT % NOT% NOT SCORE Stat ABS ABS ABS ABS ABS ABS ABS ABS Mean1 284.7 126.7 5.660.0 85.0 95.0 93.2 6.7 Mean2 294.8 129.4 5.3 70.0 92.5 55.0 85.6 4.8Locs 13 13 10 1 6 2 5 6 Reps 13 13 10 1 8 2 6 7 Diff −10.2 −2.7 0.3−10.0 −7.5 40.0 7.6 1.8 Prob 0.037 0.136 0.541 . 0.388 0.500 0.518 0.020

TABLE 2D HYBRID COMPARISON Variety #1: X6N745 Variety #2: 37N68 YIELDYIELD NLFBLT MST TSTWT GIBERS STKCNT GDUSHD GDUSLK BU/A 56# BU/A 56#SCORE PCT LB/BU SCORE COUNT GDU GDU Stat ABS % MN ABS ABS ABS ABS ABSABS ABS Mean1 175.1 95.0 7.0 18.5 55.7 9.0 62.6 121.1 121.6 Mean2 182.699.3 6.0 18.9 56.6 9.0 63.1 121.9 123.6 Locs 53 53 1 53 17 1 55 7 7 Reps58 58 1 58 18 1 60 7 7 Diff −7.6 −4.3 1.0 0.4 −1.0 0.0 −0.5 −0.7 −2.0Prob 0.001 0.001 . 0.019 0.006 . 0.118 0.140 0.004 PLTHT EARHT STAGRNSTLLPN STLPCN ERTLPN LRTLPN HSKCVR CM CM SCORE % NOT % NOT % NOT % NOTSCORE Stat ABS ABS ABS ABS ABS ABS ABS ABS Mean1 284.7 126.7 5.6 60.085.0 95.0 93.2 6.7 Mean2 284.1 120.7 6.2 100.0 99.2 95.0 99.6 5.5 Locs13 13 10 1 6 2 5 6 Reps 13 13 10 1 8 2 6 7 Diff 0.6 6.0 −0.6 −40.0 −14.20.0 −6.4 1.2 Prob 0.841 0.054 0.111 . 0.129 1.000 0.165 0.034

All publications, patents and patent applications mentioned in thespecification are indicative of the level of those skilled in the art towhich this invention pertains. All such publications, patents and patentapplications are incorporated by reference herein for the purpose citedto the same extent as if each was specifically and individuallyindicated to be incorporated by reference herein.

The foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding. Asis readily apparent to one skilled in the art, the foregoing are onlysome of the methods and compositions that illustrate the embodiments ofthe foregoing invention. It will be apparent to those of ordinary skillin the art that variations, changes, modifications and alterations maybe applied to the compositions and/or methods described herein withoutdeparting from the true spirit, concept and scope of the invention.

1. A maize variety X6N745, produced by crossing a first plant of varietyGE5339608 with a second plant of variety GE68785637, whereinrepresentative seed of said varieties GE5339608 and GE68785637 have beendeposited under ATCC Accession Number PTA-11578 and PTA-11569,respectively.
 2. A seed of the maize variety of claim
 1. 3. A plant ofthe maize variety of claim
 1. 4. A plant part of the maize variety ofclaim
 1. 5. Pollen of the plant of claim
 3. 6. An ovule or ovules of theplant of claim
 3. 7. The seed of claim 2, further comprising atransgene.
 8. The seed of claim 7, wherein the transgene confers a traitselected from the group consisting of male sterility, site-specificrecombination, abiotic stress tolerance, altered phosphorus, alteredantioxidants, altered fatty acids, altered essential amino acids,altered carbohydrates, herbicide resistance, insect resistance anddisease resistance.
 9. The plant of claim 3, further comprising atransgene.
 10. The plant of claim 9, wherein the transgene confers atrait selected from the group consisting of selected from the groupconsisting of male sterility, site-specific recombination, abioticstress tolerance, altered phosphorus, altered antioxidants, alteredfatty acids, altered essential amino acids, altered carbohydrates,herbicide resistance, insect resistance and disease resistance.
 11. Aprocess for producing a maize seed, comprising crossing the plant ofclaim 3 with itself or a different maize plant and harvesting theresultant maize seed.
 12. The process of claim 11, wherein saiddifferent maize plant is a haploid inducer.
 13. The process of claim 11,further comprising of producing an inbred corn plant derived from maizevariety X6N745, the method further comprising the steps of: (a) plantingthe resultant maize seed to produce at least one progeny plant derivedfrom maize variety X6N745; (b) crossing the progeny plant with itself ora second plant to produce seed of a progeny plant of a subsequentgeneration; (c) growing a progeny plant of a subsequent generation fromsaid maize seed and crossing the progeny plant of a subsequentgeneration with itself or a second plant; and (d) repeating steps (b)and (c) for an additional 3-10 generations to produce an inbred cornplant derived from the maize variety X6N745.
 14. A process of producinga conversion of maize variety X6N745 comprising at least one new trait,the process comprising: (a) crossing a first maize inbred variety parentplant selected from the group consisting of variety GE5339608 andvariety GE68785637, representative seed of which have been depositedunder ATCC Accession Number(s) as PTA-11578 and PTA-11569 respectively,with plants of another maize variety that comprise at least one newtrait to produce F1 seed; (b) harvesting and planting the F1 seed toproduce at least one progeny plant of the F1 generation, said progenyplant comprising the at least one new trait; (c) crossing the at leastone progeny plant with said maize inbred variety parent plant to producebackcross progeny seed; (d) harvesting and planting the backcrossprogeny seed to produce at least one backcross progeny plant, saidbackcross progeny plant comprising the at least one new trait; (e)repeating steps (c) and (d) for at least three additional generations toproduce at least a first progeny plant, wherein said first progeny plantcomprises the at least one new trait; (f) crossing the progeny plant ofstep (e) with a plant of the other maize Inbred variety of the groupconsisting of variety GE5339608 and variety GE68785637 to produce a seedthat produces a converted plant of variety X6N745, wherein the convertedplant of variety X6N745 comprises the at least one new trait.
 15. Theprocess of claim 14, wherein the at least one new trait is selected fromthe group consisting of male sterility, site-specific recombination,increased transformability, abiotic stress tolerance, herbicideresistance, insect resistance, resistance to bacterial, fungal, nematodeor viral disease, altered phosphorus, altered antioxidants, alteredfatty acids, altered essential amino acids and altered carbohydrates.16. The process of claim 14, further comprising repeating steps (a)-(f)at least once to introduce at least a second trait into corn varietyX6N745, wherein the second trait is selected from the group consistingof male sterility, site-specific recombination, increasedtransformability, abiotic stress tolerance, herbicide resistance, insectresistance, resistance to bacterial, fungal, nematode or viral disease,altered phosphorus, altered antioxidants, altered fatty acids, alteredessential amino acids and altered carbohydrates.
 17. A converted seedproduced by the process of claim
 14. 18. A converted plant produced fromthe seed of claim
 17. 19. A maize seed produced by crossing a firstplant of variety GE5339608, or a conversion thereof, with a second plantof variety GE68785637, or a conversion thereof, and harvesting theresultant maize seed, wherein representative seed of said varietiesGE5339608 and GE68785637 have been deposited under ATCC Accession NumberPTA-11578 and PTA-11569, respectively.
 20. A maize plant produced bygrowing the seed of claim 19.